Publication Date: 2025
Chemical Engineering Journal (13858947)515
Fixed-bed photocatalytic reactors with both batch and continuous flow designs were developed for the efficient treatment of oil-well produced water (OWPW). A novel three-part composite photocatalyst, MIL-101(Cr)/Fe3O4-SiO2/nano-rod-GCN, was synthesized with a high surface area (653 m2/g), a narrow visible light band gap (1.6 eV), and effective charge separation through a Z-scheme mechanism, enabling strong generation of active radicals for pollutant degradation. The photocatalytic nanoparticles were immobilized on conductive electrospun polystyrene/polyaniline fibers at various weight loadings (20, 35, 55, and 70 %). In the batch system, the fluidized three-part composite achieved a COD removal efficiency of 94.4%, while the bare polystyrene/polyaniline fibers showed only 35.7% COD adsorption under the same conditions. Immobilizing the nanoparticles onto the fibers enhanced the COD removal to 97.6%, due to the synergistic effects of hydrophobic adsorption and in-situ photocatalytic degradation. In the fixed-bed continuous flow system, under optimized conditions (solution pH 4.5, flow rate 2 mL/min, light intensity 18 W/m2, and initial COD of 700 mg/L), the stabilized photocatalyst achieved a COD removal efficiency of 92.5 %. The innovative fixed-bed continuous flow photoreactor demonstrated high and consistent performance in both adsorption and degradation, demonstrating promising applicability for real-world treatment of produced water. © 2025 Elsevier B.V.
Mosallanezhad, M.,
Farahmand, R.,
Solaimany nazar a.r., A.R.,
Farhadian, M.,
Karimi, H.R. Publication Date: 2025
Materials Science and Engineering: B (09215107)321
MIL-101-OH, a hydroxyl-functionalized metal–organic framework (MOF), was synthesized as a nanostructured adsorbent to detect and eliminate methylene blue (MB) and cefixime (CEF) from aqueous solutions. To improve its interaction with pollutants, MIL-101 was post-synthetically modified with hydroxyl group. BET analysis showed a specific surface area of 1367 m2/g, and FTIR and XRD analyses verified the structural integrity and successful functionalization. The uniform distribution of particle sizes was shown by SEM imaging. To enable detection based on changes in the refractive index, the functionalized MOF was also used as a coating material on an optical fiber sensor. CEF and MB had maximum adsorption capacities of 328 mg/g and 358 mg/g, respectively. The results demonstrate the potential of MIL-101-OH for simultaneous adsorption and optical sensing applications in water treatment. The sensor demonstrated a linear dynamic range of 0–10 mg/L with response times of 75and 32 s for CEF and MB, respectively. © 2025 Elsevier B.V.
Publication Date: 2025
Journal of Polymer Research (15728935)32(3)
Polystyrene (PS) fibers were fabricated via one-step electrospinning process, using tetrahydrofuran (THF) and N, N-dimethylformamide (DMF) as mixed solvent. The properties and structure of fibers were characterized by XRD, FTIR, DSC, FESEM, BET, and tensile strength analyses. The effect of operating parameters on the fiber structure in the electrospinning process was evaluated using the Taguchi experimental design. The production of fibers with a uniform surface, dense nanopores, and bead-free morphology can be controlled by optimizing the electrospinning conditions. For this purpose, the effects of solvent composition, solution concentration, feeding rate, and applied voltage were studied. The performance of the fibers was evaluated through adsorption and selectivity tests. The adsorption capacity of the fibers was measured using three different oil sources: sunflower oil, motor oil, and crude oil. The selectivity performance of the fibers was assessed with dispersed and dissolved crude oil in water. The results revealed that the maximum oil adsorption capacities of PS fibers for sunflower oil, motor oil, and crude oil were 58.4, 68.5, and 61.1 g/g, respectively. Furthermore, the PS fibers demonstrated excellent oil–water selectivity in the treatment of oily water. Moreover, polyaniline (PANI) was incorporated as a conductive polymer to enhance the properties of electrospun fibers. The conductive fibers exhibited improved microstructural properties and performance compared to PS fibers. The motor oil adsorption capacity increased to 71.5 g/g with the conductive PS/PANI fibers. The results of this study demonstrate that the conductive and hydrophobic PS/PANI fibers, as selective adsorbents, possess a high capacity for the adsorption of various oils. © The Polymer Society, Taipei 2025.
Publication Date: 2025
Environmental Science and Pollution Research (09441344)32(10)pp. 6244-6272
An innovative ternary heterostructure, MIL-101(Cr)/Fe3O4-SiO2/nanorod-graphitic carbon nitride (MIL-Cr/F@S/nr-GCN), was synthesized by hydrothermal technique. Comprehensive physiochemical characterizations were conducted to elucidate the structural and optical properties. The synthesized photocatalysts were evaluated for adsorption and photodegradation of oil well–produced water pollutants. Remarkably, the ternary heterostructure composite with 20 wt% of nr-GCN exhibited superior photocatalytic performance compared to nr-GCN and the MIL-Cr/F@S binary composite. Under visible-light illumination, the maximum removal efficiency of chemical oxygen demand for synthetic oil well–produced water reached 97.4% under optimized conditions (pH 4, illumination time 90 min, photocatalyst dosage 0.6 g/L, and pollutant initial concentration 754 mg/L). Adsorption studies revealed adherence to the pseudo-second-order kinetic and Freundlich isotherm models The ternary composite displayed degradation rates 2.8 and 2 times higher than nr-GCN and MIL-Cr/F@S, respectively. This enhanced activity was attributed to the double Z-scheme configuration, providing high specific surface area (653 m2/g), appropriate bandgap energy (1.6 eV), and efficient charge carrier separation. Moreover, the ternary photocatalysts demonstrated excellent reusability over five cycles without Cr ions leaching into the water. These findings underscore the potential of the novel ternary heterostructure as a green and robust photocatalyst for oil well–produced water treatment. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Asadpoor, M.,
Fakharzadeh, M.,
Fazljoo, S.E.,
Ardjmand, M.,
Farhadian, M.,
Omidkhah, M.,
Zinatizadeh, A.A. Publication Date: 2025
Chemical Papers (03666352)79(6)pp. 3739-3752
This study presents a promising technology for the degradation of azo dye (Acid black 172 (AB 172)) using a modified TiO2 anode. CNT-TiO2-BiOBr-Bi2S3 was synthesized and deposited on the anode electrode, and a graphite sheet was selected as the cathode in a photoelectrochemical oxidation process. The CNT-TiO2-BiOBr-Bi2S3 composite photocatalyst significantly advances visible light-driven photocatalytic systems, outperforming conventional catalysts due to synergistic interactions among its components. The morphology, chemical composition, and optical properties of the CNT-TiO2-BiOBr-Bi2S3 catalyst were investigated by XRD, FTIR, FESEM, EDX, PL, and UV–Vis analyses, respectively. The effects of the processing factors and their statistical optimization values were determined using response surface methodology. The results showed that increasing the light intensity and irradiation time enhanced the photoelectrochemical degradation of the azo dye. In contrast, increasing the dye concentration leads to a decrease in degradation efficiency and COD removal. The acidic medium is beneficial in improving the removal efficiency of AB 172. Complete removal of AB 172 was achieved under optimal degradation parameters, including pH = 4, an AB 172 concentration of 15 mg/L, an irradiation time of 7 h, and a light intensity of 500 lm. COD removal and current density were about 90% and 200 µA, respectively, under optimal conditions. The anode and cathode reusability were examined, showing that the photoelectrochemical process effectively degrades contaminants, even after four electrode reuse cycles. This study demonstrates the potential of using reusable CNT-TiO2-BiOBr-Bi2S3 electrodes for visible light-responsive and sustainable water and wastewater treatment technology. © The Author(s), under exclusive licence to the Institute of Chemistry, Slovak Academy of Sciences 2025.
Publication Date: 2025
PLOS Water (27673219)4(12)
The ZnO/BiOBr/Bi2S3 dual Z-scheme heterojunction was synthesized via the solvothermal method, and the photocatalytic removal of cefixime (CFX) was investigated using the nanocomposite. Structural and morphological studies were conducted using XRD, FTIR, Raman spectroscopy, XRF, FE-SEM, TEM, UV-Vis DRS, PL, and BET. The results indicated that the ZnO/BiOBr/Bi2S3 exhibited a synergistic effect, reducing the band gap energy to 2.70eV and enhancing charge separation in comparison with individual and binary components. The Raman peak shifts confirmed the formation of heterojunction among the components. Optimization of the mass ratio through screening experiments resulted in an optimum composition of 30 wt% ZnO to BiOBr/Bi2S3, achieving a 75% removal efficiency. CFX adsorption on the nanocomposite followed a monolayer mechanism, with a maximum adsorption capacity of 15.32mg.g-1. In addition, approximately 96% CFX removal was achieved using the immobilized ternary ZnO/BiOBr/Bi2S3 heterojunction on graphite under optimal operating conditions. The O2–•and h+ for the suspended and the O2–•and OH• for the immobilized system play the major role in CFX degradation. © 2025 Rahpeyma et al.
Publication Date: 2025
Scientific Reports (20452322)15(1)
The presence of antibiotic pollutants such as tetracycline (TC) in water bodies poses a major environmental and health concern due to their persistence and resistance to conventional treatment. To address this issue, a novel GAs/Bi2O3/ZIF-67 composite was synthesized and coated onto graphite plates using a spin-coating method. This composite was integrated into a planar microreactor system comprising conductive FTO glass and a PDMS spacer, designed to enhance photocatalytic performance through simultaneous application of a low-voltage electric current. The composite was characterized using XRD, UV-Vis-DRS, FTIR, PL, SEM, EDX, TEM, EIS, and Photocurrent techniques. Photocatalytic activity was evaluated under various operational parameters. Under optimized conditions (pH = 4, the concentration of TC/load of photocatalyst = 0.2 (mg.m2/g.L), and retention time = 360 s), applying 1.8 V increased degradation efficiency from 88 to 99% and reduced treatment time by 33%. A synergistic index of 1.66 confirmed the positive interaction between photocatalysis and electric current. Kinetic studies indicated that the reaction rate was the limiting factor. The system maintained an efficiency of over 80% for 780 min, exhibiting stable performance under flow reversal. These results demonstrate the system’s potential as a fast, scalable, and energy-efficient approach for treating industrial pharmaceutical wastewater. © The Author(s) 2025.
Publication Date: 2025
International Journal of Biological Macromolecules (01418130)328
The persistent presence of Metronidazole (MTZ), a commonly used antibiotic, in water bodies is a serious environmental and health concern because of its genotoxic and carcinogenic potential. Here, we report an effective visible-light photocatalyst system comprising an S-scheme glycine–modified TiO2/Fe3O4 heterojunction immobilized on chitosan–polyacrylonitrile nanofibers. The photocatalyst nanocomposite was synthesized through a sol–gel and ultrasonication process coupled with electrospinning-assisted immobilization. Structural, morphological, and optical studies corroborated the successful formation of the heterojunction, enhanced light absorption, reduced electron–hole recombination, and elevated charge separation. Photocatalytic activity was evaluated in a visible light batch slurry photoreactor with as high as 95.7 % MTZ removal under optimal conditions (initial concentration: 40 mg/L, pH 4.5, catalyst dosage: 0.50 g/L, irradiation time: 120 min), with only around 3 % deviation from the design of experiments (DOE) model's predicted value (∼ 98.9 %). The composite exhibited high reusability with over 85 % retention of its photocatalytic activity over five cycles. © 2025 Elsevier B.V.
Arabian, S.,
Gordanshekan, A.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Tangestaninejad, S.,
Sabzyan, H. Publication Date: 2024
Chemical Engineering Journal (13858947)488
This study investigated the photocatalytic adsorption, degradation, and mineralization of Cefixime (CFX) through hydrothermally synthesized Bi2WO6(36 %)/g-C3N4(54 %)/ZIF-67(10 %) dual S-scheme heterojunction (BCZ). Full characterization analysis for the fresh and reused photocatalyst was explored to study the formation of heterojunction, stability, and reusability of the BCZ. VB-XPS, Mott-Schottky plots, and UV–Vis DRS defined the band structure and electron transfer mechanism of BCZ. The effects of ten operating condition factors, including reaction time, initial concentration of CFX, the dosage of photocatalyst, reaction temperature, initial pH of the reaction, visible and UV intensity, and concentration of Na2SO4, NaOH, and NaCl in the reaction solution were experimentally investigated. These factors were then modeled through artificial neural networks (ANN). The number of neurons, training algorithm, and the type of activation functions in the ANN were optimized by mean squared error metric followed by the visualizations of the ANN predictions. Two cost functions (the ratio of instantaneous CFX concentration to initial CFX concentration (C/C0) and the ratio of photocatalyst dosage to the amount of CFX removed) were employed to optimize the value of these operating condition factors separately and simultaneously through single and multi-objective genetic algorithms. Coupling LC-MS results and DFT calculations, a degradation pathway for Cefixime was proposed and then analyzed by QSAR. The toxicity of the treated solution was investigated using the wheat seed culture, along with MIC and MBC testing conducted by E. coli and S. aureus, and its eco-friendliness was confirmed by TOC and COD. Furthermore, ICP-OES confirmed that BCZ is a green photocatalyst. © 2024 Elsevier B.V.
Ashrafi, M.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Hajiali, M. Publication Date: 2024
Applied Surface Science (01694332)662
Background: Contamination of water with antibiotics poses environmental challenges. Photocatalytic semiconductor heterostructure technologies prove effective in water purification, particularly in eliminating pharmaceutical pollutants. Achieving high-quality heterostructures remains a considerable challenge. Methods: ZnO/Bi2MoO6/ZIF-67 photocatalyst was synthesized using the ambient temperature method and characterized through XRD, FTIR, SEM, EDX, TEM, UV–vis DRS, TGA, PL, and BET analyses. Significant findings: The novel ZnO/Bi2MoO6/ZIF-67 photocatalyst's efficacy in degrading tetracycline under visible light was evaluated. The optimal composite molar ratio of ZnO: Bi2MoO6: ZIF-67 was found to be 1:0.6:0.157, exhibiting superior photocatalytic performance compared to ZnO, Bi2MoO6, and ZIF-67. With ZnO/Bi2MoO6/ZIF-67, the highest removal efficiency of tetracycline reached 90.3 % under ideal conditions (catalyst dose = 0.4 g/L, pH = 6.5, irradiation time= 90 min, tetracycline concentration = 40 mg/L). The photocatalytic degradation of tetracycline follows first-order kinetics. The trapping experiments showed that OH• and •O2– species played a beneficial role in enhancing the photodegradation process. © 2024 Elsevier B.V.
Publication Date: 2024
Journal of Industrial and Engineering Chemistry (1226086X)130pp. 623-637
A new high-efficiency continuous photocatalytic system composed of a microreactor and an optical fiber coated with a ZnO nanorod array/TiO2/GO with a retention time of 4–7 min was introduced. Using a new step-by-step chemical bath deposition method, a ZnO nanorod array coated with TiO2 and GO was grown on the surface of an optical fiber with different mass ratios. The coated photocatalytic layer was characterized using XRD, XPS, Raman spectra, UV-drs, TEM, and SEM. The photocatalytic degradation efficiency of Cefixime (CEF) in the microreactor was studied under irradiation from two diffusing and focusing light sources to determine the effect of light radiation type on the efficiency. ZnO nanorods/TiO2 coated optical fiber (Ti/Zn weight ratio = 0.37) and GO deposition during the growth of ZnO nanorods demonstrated the highest degradation efficiency. The operational and geometrical parameters were optimized as fiber length = 15 cm, fiber diameter = 500 µm, CEF concentration = 10 ppm, and pH = 4.8. The removal efficiency under these conditions was approximately 67 % with a diffused light source and 80.1 % with a focused light source. The coated photocatalytic composite showed high stability to the liquid flow after 1200 min of continuous operation, indicating the ZnO nanorods/TiO2/GO coating method's success. © 2023 The Korean Society of Industrial and Engineering Chemistry
Publication Date: 2024
Renewable Energy (09601481)226
Photocatalytic fuel cell (PFC) systems can be a new generation of energy production by simultaneously producing electricity and removing organic pollutants from aqueous solutions. A baffling photoreactor is developed for application in a PFC, and the continuous system consists of a light-responsive photoanode (ZnO/Bi2MoO6/MIL-101; ZnO/Bi2MoO6; ZnO) and a photocathode (Cu/CuO/Cu2O). A response surface method (RSM) is presented to characterize the process factors (pH, immobilized catalyst dosage (mg/cm2), and tetracycline concentration (ppm)) on the performance of a reactor designed to optimize degradation efficiency and maximum power generation. The optimal conditions are determined at pH = 7, Catalyst dosage = 0.87 mg/cm2, and tetracycline concentration = 80 ppm. In optimal conditions, other parameters for degradation efficiency (88.8%), open circuit voltage (1.03 V), short circuit current (2.5 mA/cm2), and maximum power generation (0.87 mW/cm2) are obtained. The performance of different photoanodes by linear sweep voltammetry shows a current density of 2.5 mA/cm2 for ZnO/Bi2MoO6/MIL-101, which is 7.8 and 1.8 times higher than ZnO and ZnO/Bi2MoO6 photoanodes, respectively. The flow regime is determined by residence time distribution (RTD) in the novel reactor with the experimental data of 6 tanks-in-series. © 2024 Elsevier Ltd
Publication Date: 2024
Journal of Environmental Sciences (China) (10010742)141pp. 287-303
Graphitic carbon nitride with nanorod structure (Nr-GCN) was synthesized using melamine as a precursor without any other reagents by hydrothermal pretreatment method. XRD, FTIR, SEM, N2 adsorption-desorption from BET, UV–Vis DRS spectroscopy, and photoluminescence were used to characterize the prepared samples. Also, the photoelectrochemical behavior of nanoparticles was studied by photocurrent transient response and cyclic voltammetry analysis. Polystyrene (PS) fibrous mat was fabricated by electrospinning technique and used as a support for the stabilization of the nanoparticles. The performance of the synthesized nanoparticles and photocatalytic fibers (PS/Nr-GCN) was evaluated in oilfield-produced water treatment under visible light irradiation. During this process, oil contaminants were adsorbed by hydrophobic polystyrene fibers and simultaneously degraded by Nr-GCN. The removal efficiency of chemical oxygen demand (COD) has been obtained 96.6% and 98.4% by Nr-GCN and PS/Nr-GCN, respectively, at the optimum conditions of pH 4, photocatalyst dosage 0.5 g/L, COD initial concentration 550 mg/L, and illumination time 150 min. The gas chromatography-mass spectroscopy analysis results showed 99.3% removal of total petroleum hydrocarbons using photocatalytic fibers of PS/Nr-GCN. The results demonstrated that the GCN has outstanding features like controllable morphology, visible-light-driven, and showing high potential in oily wastewater remediation. Moreover, the synergistic effect of adsorption and photocatalytic degradation is an effective technique in oilfield-produced water treatment. © 2023
Ashrafi, M.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Hajiali, M.,
Noorbaksh, A. Publication Date: 2024
Energy Conversion and Management (01968904)312
In the Photocatalytic fuel cell microreactor system, a three-component photocatalyst powder of ZnO nanorod/Bi2MoO6/ZIF-67 was synthesized and deposited as a photoanode immobilize on an FTO substrate using the drop-casting method. The electrochemical properties and photocurrent obtained in the ZnO/Bi2MoO6/ZIF-67 photoanode/FTO system exceeded those of ZnO/Bi2MoO6/FTO and ZnO/FTO. The use of the ZnO/Bi2MoO6/ZIF-67 composite on the FTO substrate led to a reduction in the bandgap energy from 1.74 ev to 1.61 ev. The optimal conditions for tetracycline degradation included a tetracycline concentration of 20 ppm, a pH of 7, light intensity of 7.9 mW/cm2, and a flow rate of 120 µL/min. Under these conditions, the removal efficiency and TOC were calculated as 97.16 % and 92.4 %, respectively. The maximum power density was 35.1 mW/cm2, and the photocurrent density was 1.4 mA/cm2. The kinetics of tetracycline removal in the microreactor input followed the Langmuir-Hinshelwood model, and mass transfer resistance in the fluid phase did not significantly affect the reaction kinetics. Additionally, the time-on-stream (TOS) curve indicated that the removal efficiency dropped below 80 % after 1450 min of operation, reaching a breaking point. © 2024 Elsevier Ltd
Publication Date: 2023
Chemical Engineering Journal (13858947)451
This study comprehensively compared two hydrothermally synthesized S-scheme heterojunctions, Bi2WO6/g-C3N4 and Bi2WO6/TiO2. The photocatalytic removal of cefixime (CFX) was used to screen the different mass ratios of the components for each heterojunction. Photocatalytic adsorption/degradation and operational effects such as initial pH, the ratio of CFX concentration to the photocatalyst load, light intensity, UV irradiation, and the presence of anions were compared and evaluated. The adsorption isotherms and kinetics of the photocatalytic adsorption and degradation were studied. Furthermore, the band structure was investigated by valence band X-ray photoelectron spectroscopy (VB-XPS), Mott-Schottky plot, and UV–vis DRS. The mechanism of the photocatalytic reaction under visible and UV–vis irradiation was comprehensively investigated by scavenger tests and electron spin resonance (ESR). The photocurrent response, EIS, and linear sweep voltammetry (LSV) results confirmed the photocatalytic enhancement of the heterojunctions. The leaching of metal ions, reusability, and performance of the heterojunctions were investigated for 6 cycles. The photocatalytic degradation pathway of CFX and the toxicity of the by-products were investigated by LC-MS and Toxicity Estimation Software Tool (T.E.S.T). After 135 min of photocatalytic reactions, the TOC removal efficiency of CFX was 94 % and 91 % for Bi2WO6/g-C3N4 and Bi2WO6/TiO2. CFX and the by-products were entirely mineralized after 180 min of the reactions. It was found that the binary heterojunctions and the photocatalytic reactions are green and environmentally friendly. The optimized artificial neural network with 18 neurons simulated the experiments. The trained feed-forward network was able to successfully simulate different operating conditions and different mass ratios of the heterojunctions. © 2022 Elsevier B.V.
Publication Date: 2023
Applied Surface Science (01694332)613
A visible-light driven superhydrophobic composite of MIL-101(Cr)/Fe3O4-SiO2 was synthesized via hydrothermal method. Various physicochemical techniques were employed for the characterization of the nanoparticles such as XRD, FTIR, FESEM, TEM, EDS, BET, UV–Visible DRS, PL, and pHpzc. The adsorption and photocatalytic performance of the synthesized nanoparticles were evaluated by synthetic and real oilfield produced water (OPW) treatment. The optimal loading amount of Fe3O4-SiO2 was determined by analysis tests and investigation of photocatalytic activity. The results showed that the superhydrophobic composite with 35% weight percent of Fe3O4-SiO2 exhibited the maximum removal efficiency. Effect of operational parameters such as pH, reaction time, and initial concentration of pollutants on the removal efficiency were evaluated. The chemical oxygen demand (COD) removal efficiency of synthetic oilfield produced water (SOPW) achieved 95.17% and 96.6% under visible and UV light irradiation by MIL-101(Cr)/Fe3O4-SiO2 (35%), at the optimum conditions of pH 4, photocatalyst dosage 0.5 g/L, COD initial concentration 600 mg/L, and illumination time 150 min. Moreover, the gas chromatography-mass spectroscopy (GC–MS) analysis results showed 97.7% and 99.2% removal efficiency of total petroleum hydrocarbons (TPH) for real and synthetic OPW, respectively. The results of kinetic and isotherm study showed that the kinetic data followed the pseudo-second-order and equilibrium adsorption was described by the Freundlich model. The high specific surface area, narrow bandgap energy as well as the charge carrier separation based on the Z-scheme heterostructure caused the improvement of binary composite photocatalyst features. The results demonstrated that the MIL-101(Cr)/Fe3O4-SiO2 superhydrophobic composite are promising photocatalyst in the degradation of oilfield produced water pollutants. Synergistic effect of adsorption and photocatalytic degradation of OPW help to enhance the removal performance. © 2022 Elsevier B.V.
Publication Date: 2023
International Journal of Environmental Science and Technology (17351472)20(2)pp. 1645-1672
Water pollution is one of the biggest problems in world today, which is directly related to the progress and development of the countries. Using the adsorbents of porous nanostructures, called metal–organic frameworks (MOFs), for the removal of pharmaceutical pollutants is a novel technology. HKUST-1/ZIF-8 nanocomposite was synthesized using a facile and green ultrasonic method and characterized to establish selective adsorption properties of a wide range of drug contaminants and higher water stability than HKUST-1 in water. Moreover, the adsorption of cefixime (CFX) and lamotrigine (LTG) on ZIF-8, HKUST-1, Fe3O4/HKUST-1, Fe3O4/ZIF-8, HKUST-1/ZIF-8, and activated carbon was compared. Regarding acid–base interactions, the adsorption capacity of drugs with the amine group on ZIF-8 and drugs with an acidic functional group on HKUST-1 was very low. The nanocomposite could remove drugs with amine groups and acidic functional groups with appropriate adsorption capacity and water stability from aqueous media. At 25 °C, pH 7, and a contact time of 240 min, the maximum adsorption capacity of CFX on HKUST-1/ZIF-8 composite was 110 mg/g, which was three times (38 mg/g) greater than that of HKUST-1. The maximum adsorption capacity of LTG on HKUST-1/ZIF-8 composite was 139 mg/g which was 1.5 times (101 mg/g) as large as that of ZIF-8. Hydrogen bonding, electrostatic interaction, and acid–base interaction might be responsible for the adsorption of drugs. By adding Fe3O4 to MOFs, the synthesized materials become superparamagnetic and could be easily separated from the water using a magnetic field. Nevertheless, magnetic ZIF-8 could be used for 5 cycles with the removal efficiency of around 90% post-recycling, while magnetic HKUST-1 could be applied for 3 cycles because of its low stability. Based on correlation coefficient (R2), Langmuir isothermal model and pseudo-second-order model were chosen for the adsorption of CFX and LTG, respectively. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.
Publication Date: 2023
Journal of Molecular Liquids (18733166)377
The Bi2WO6/N-TiO2 composite was synthesized hydrothermally, and characterized by using XRD, XRF, FE-SEM, EDX, FT-IR, BET, PL, and UV–VIS DRS analyses. The improvement in the catalytic activity of the prepared composite is related to lower recombination, and narrow band gap. The degradation of Acid Black 172 was examined under continuous conditions by using a tray photoreactor in which the catalyst was supported on the FTO through spin coating. The effect of independent factors such as initial pH (5–9), contaminant to photocatalyst mass ratio (10–30 mg/g), and flow rate (1.5–4.5 ml/min) on the degradation efficiency was investigated. The results indicated that at the optimum conditions of pH = 5, contaminant to photocatalyst = 10 mg/g, flow rate = 1.5 min/mL, textile color removal efficiency was 81%, and TOC removal efficiency was 75% under visible light intensity = 20 w/m2. In addition, a decrease and an increase in degradation in the presence of mineral salts and more light intensity under optimum conditions, respectively. The degradation efficiency decreased slightly after several uses which confirmed the good performance and reusability of the catalysts. © 2023 Elsevier B.V.
Publication Date: 2023
Advances In Environmental Technology (24764779)9(4)pp. 339-350
The lab-scale treatment of strong beet sugar wastewater was carried out with a combination of a moving bed biofilm reactor (MBBR) and upflow sludge blanket filtration (USBF). The hybrid bioreactor was filled (35% of volume) with industrial packings made of polyethylene with an effective surface area of 480 m2/m3 to provide the necessary surface for biofilm growth. The effect of various operating conditions, including hydraulic retention time (HRT = 12-20 hr), biomass concentration (6000– 8000 mg/L), and initial chemical oxygen demand (COD) (3000-5000 mg/L) level, were assessed on the overall COD removal efficiency using response surface methodology (RSM). The optimal conditions were an HRT = 20 hr, biomass concentration = 8000 mg/L, an initial COD = 3000 mg/L, and an organic loading rate (OLR) of 3.6 kg COD/m3.day under which the COD removal efficiency was 98%. The modified Stover– Kincannon model was applied to predict the biokinetic coefficients for COD removal; the saturation constant (KB) and the maximum total substrate utilization rate (Umax) were in the range 58-101.6 and 57.5-97 as g/L.day, respectively. The results revealed that raising HRT or biomass concentration promoted COD removal while increasing the initial COD deteriorated the removal performance. © ️2023 Advances in Environmental Technology (AET).
Publication Date: 2023
Process Safety and Environmental Protection (17443598)176pp. 87-100
To take advantage of solar energy, BiVO4/ZIF-8/Cu2S/Ag2S quaternary photocatalyst with different amounts of ZIF-8 was synthesized. Composites were characterized by FTIR, XRD, TEM, HR-TEM, PL, EDX, DRS and BET. The photocatalytic performance was evaluated and composite with 77.5, 15, 5 and 2.5 wt% of BiVO4, Cu2S, Ag2S and ZIF-8 showed the best qualification with 83.5 % metronidazole removal efficiency. Photocatalytic nanoparticles were incorporated into ABS/MWCNT membranes and they were characterized by SEM, EDX, AFM, electrical conductivity and contact angle measurements. The membrane with 2 wt% MWCNT had conductivity 106 times higher than that of pristine ABS membrane. The contact angles were decreased and the membrane with a more hydrophilic surface resulted in the flux improvement to 200 kg/m2. h. The enhanced drug retention up to 81 % indicated that by using the proper amount of photocatalyst it was possible to increase both the flux and rejection parameters. The flux recovery after solar illumination was obtained as 95.6 % for membrane with 0.5 wt% photocatalytic composites, that result in appropriate anti-fouling capability. finally, high performance photocatalytic activity makes membrane with 0.5 wt% photocatalyst and 1 wt% MWCNT superior for long-life filtration (36 h). © 2023 The Institution of Chemical Engineers
Publication Date: 2023
Energy (18736785)272
Photocatalytic fuel cells (PFC) provide a new approach to organic pollutants degradation from wastewater and energy generation. A new type of dual photocatalytic fuel cell (PFC) consisted of a ZnO NRs/BiOBr/UiO-66-NH2 (ZBU) photoanode and a Cu2O/CuO/Cu photocathode was constructed for tetracycline (TC) degradation, and simultaneously electricity production. The photodegradation and electrochemical properties gained at the ZBU/FTO photoanode are better than those of ZB/FTO and ZnO/FTO. The synthesized electrodes were characterized by XRD, FE-SEM, EDX, TEM, UV–Vis DRS, and PL analyses. The tests performed in the PFC system displayed that the closed-circuit removal efficiency is better than that in the open-circuit. At optimum conditions: light intensity = 10.13 mW/cm2, time = 45min, pH = 6.8, and TC concentration = 20 mg/L, the efficiency of TC degradation and the maximum output power were obtained at 97.1%, and 29.26 μW/cm2, respectively. The effects of the NaCl, NaHCO3, and Na2SO4 electrolytes were evaluated, and the current density of the Na2SO4 electrolyte was about 1.8 and 1.5 times higher than those of the NaHCO3 and NaCl electrolytes, respectively. The new PFC system showed well reusability after four cycles. © 2023
Publication Date: 2023
Journal of Applied Electrochemistry (15728838)53(1)pp. 65-83
A visible light-mediated degradation of metronidazole (MNZ) was performed via Electro-photo-Fenton (EPF) with TiO 2/reduced graphene oxide (5 wt%)/Fe 2O 3 (4 wt%) photocatalysts deposited onto graphite cathodes. The synthesized photocatalyst was immobilized by the dip-coating method. The central composite design was used to examine the effect of current density, irradiation time, pH, contaminant concentration, and catalyst concentration. The optimal conditions for MNZ degradation were obtained at a concentration of 25 mg L - 1 via EPF method with a reaction time of 100 mins, pH of 4.6, and current density of 2.5 mA cm - 2. The amount of catalyst used under such conditions was 0.2 mg L - 1. The results of the characterization analysis based on Fourier-transform infrared spectroscopy, photoluminescence, X-ray diffraction, Ultraviolet–visible diffuse reflection spectroscopy, Field emission scanning electron microscopy, X-ray fluorescence, Energy-dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller confirmed that the photocatalyst was synthesized and deposited on graphite cathode uniformly. Experimental data revealed that the removal of MNZ by suspended photocatalysts, Electro-Fenton, and Electro-photo-Fenton yielded 56.9%, 61.4%, and 82%, respectively. In this study, a combined EPF with suspended photocatalyst yielded a 90.8% removal efficiency of MNZ. With a modified cathode in the EPF process, the removal efficiency and mineralization were achieved within 100 mins as 96.7% and 88.5%, respectively. There was adequate stability after repeating the experiment five times with the same modified cathode at the optimum point in the integrated experiments. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Nature B.V.
Publication Date: 2023
Advanced Powder Technology (15685527)34(8)
A photoelectrochemical degradation of reactive blue 19 (RB19) and electricity generation was modeled and optimized in a photocatalytic fuel cell with CNT/TiO2/WO3/CdS/FTO photoanode and Cu2S/FTO photocathode using response surface methodology-central composite design. The coated photocatalyst on fluorine-doped tin oxide (FTO) was characterized by surface and cross-section FESEM, EDX spectrum, EDS mapping, XRD, and DRS analysis. The CNT/TiO2/WO3/CdS and Cu2S were coated on FTO glass by applying the dip coating and combined dip coating-SILAR method, respectively. The efficiency of RB19 and Chemical oxygen demand removal under the optimum circumstances of 15 mg/L dye concentration, pH = 4, and the light intensity of 890 lm were obtained at 99.9 % and 70 % after 4.5 h, respectively. Moreover, the generated current density during the photocatalytic process was calculated at about 41.3 µA/cm2 after 90 min. The effect of air injection, open and closed electrical circuits, light radiation, and adsorption rate of photocatalysts on RB19 removal was examined. The five times reusability confirmed the good stability and photoactivity of coated catalyst on the FTO electrodes at the optimum conditions. The result indicated that the photocatalytic fuel cell is an excellent technology not only for wastewater treatment but also for energy production. © 2023 The Society of Powder Technology Japan
Publication Date: 2023
Chemical Engineering and Processing - Process Intensification (02552701)188
Tetracycline degradation was investigated using two promising technologies of photocatalysis and photoelectrochemical oxidation through Bi2O3/ZIF-67 nanocomposite coating on a graphite plat (Bi2O3/ZIF-67@GP). The physical, chemical and morphological properties of coated graphite plat were determined by XRD, SEM, EDX, CROSS, UV–Vis DRS, and PL. Photocatalytic process in optimal process conditions (pH=4.1, pollutant concentration/load of photocatalyst =0.26 mg.m2/g.L and irradiation time=86 min) showed 77% pollutant removal efficiency. The use of photoelectrochemical oxidation processes has a positive effect on the efficiency of pollutant removal, at optimal conditions (Electrode distance=5.5 mm, pH=4, voltage=1.8 V, Time=89 min, and pollutant concentration/photocatalyst load= 0.2 mg.m2/g.L), the result was showed that 97% tetracycline removal efficiency. The effect of the water matrix including NaCl, Na2SO4, NaHCO3, KCl, MgSO4, and CaCl2 in different concentrations (100–800 mg/L) was recast the initial pH=7, and the pollutant concentration/photocatalyst load=0.2 mg.m2/g.L, and the time=90 min. The investigation and results showed that the presence of inorganic cations and anions caused a constant decrease in the reaction rate. © 2023 Elsevier B.V.
Publication Date: 2022
International Journal of Biological Macromolecules (01418130)208pp. 260-274
A Z-scheme Bi2WO6/CNT/TiO2 photocatalyst was synthesized hydrothermally and loaded on chitosan nanofibers with different mass percentages using the electrospinning process. The batch adsorption experiments for chitosan nanofibrous samples containing Bi2WO6/CNT/TiO2 revealed that the adsorption process and its kinetic followed the Langmuir isotherm and pseudo-second-order model, respectively. A planar microreactor with a reusable plate-type configuration was fabricated employing an inexpensive micromachining technique and integrated with chitosan/Bi2WO6/CNT/TiO2 nanofibers. The synergistic effect of the adsorption and photocatalysis was assessed for removing cephalexin under simulated sunlight irradiation in a continuous flow microreactor. The nanofibers containing 15 wt% of Bi2WO6/CNT/TiO2 exhibited the most removal efficiency. The effects of operational variables were investigated in the microreactor and optimized using response surface methodology as light intensity = 17.45 W/m2, retention time = 256 s, pH = 4.8, and initial cephalexin concentration = 29 mg/L. At this condition, cephalexin and TOC removal efficiencies reached 99.2% and 92.4%, respectively. The kinetic of disappearance of cephalexin under optimal conditions followed the Langmuir-Hinshelwood model. The adsorption equilibrium constant deduced from this model was similar to that one calculated from the Langmuir isotherm model. At the optimum condition, cephalexin removal efficiency reduced to 80% after 1500 min of microreactor operation and the nanofibers revealed appropriate stability and reusability. © 2022
Publication Date: 2022
Environmental Technology (United Kingdom) (1479487X)43(9)pp. 1269-1284
The visible active N-doped TiO2/ZnFe2O4 (urea–TiO2/ZnFe2O4) and CN-codoped TiO2/ZnFe2O4 (L-asparagine–TiO2/ZnFe2O4) nanocomposites were successfully synthesized by the sol–gel–hydrothermal method for direct red 16 (DR16) photodegradation. Their properties of the prepared nanocomposites were analysed using XRD, FT-IR, FE-SEM, EDX, DRS and PL tests. The DRS and PL results confirmed a narrow band-gap energy and low recombination rate of photo-produced electron and hole pairs, respectively. The effect of adding various dopant agents (urea and L-asparagine) with different loadings and magnetic nanoparticle (ZnFe2O4) into TiO2 sol on the photodegradation of DR16 was also evaluated. As a result, the L-asparagine (2 wt. %)–TiO2/ZnFe2O4 is the best photocatalyst compared to the other modified TiO2 nanocomposites due to its narrow band gap and high quantum efficiency. The catalyst concentration (1–2 g/L), DR16 concentration (25–45 ppm), initial pH (4–10), and irradiation time (30–90 min) as numerical variables were also considered for photocatalytic process analysis and moulding by central composite design (CCD). The increase in the pH and dye concentration reduces the photodegradation efficiency while irradiation time and catalyst concentration effectively improved its photodegradation efficiency. The DR16 was completely removed at 25 ppm of DR16, initial pH of 4 and 1.5 g/L of photocatalyst after 90-min irradiation. The photoactivity test was also repeated four times by reused L-asparagine–TiO2/ZnFe2O4 photocatalyst at optimum conditions. The decrease of dye degradation and loss of photocatalyst were not significant which was approved by the good performance and high recovery capability of the prepared nanocomposite. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Publication Date: 2022
Environmental Science and Pollution Research (09441344)29(46)pp. 69502-69516
The removal of ibuprofen (IBP) from the aqueous solution by metal–organic frameworks such as UiO-66, UiO-66-NH2, and a binary MOF (UiO-66@5%HKUST-1) was studied. MOFs were synthesized by the solvothermal method. The synthesized MOFs were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption. BET results showed that binary MOF and UiO-66-NH2 had a smaller surface area and were mesoporous compared to UiO-66, while UiO-66 was microporous. Quantitative investigations were conducted to understand the effect of binary and functional UiO-66 in adsorbing IBP and compared to UiO-66. The results showed that UiO-66 with 213 mg/g had the highest adsorption in comparison to other adsorbents. UiO-66-NH2 showed the lowest adsorption (96 mg/g) due to a large decrease in the surface area. The binary MOF, despite a slight decrease in surface area (1277.6 m2/g), had lower adsorption than UiO-66 (147 mg/g) due to the antagonistic effects between the adsorbent and IBP. Furthermore, the pH of the solution had a great effect on the adsorption of IBP, and the results showed that increasing the pH values above 4 reduced the adsorption of IBP. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Publication Date: 2022
Iranian Economic Review (10266542)26(2)pp. 459-476
Value for money assessment is used in Iran to select appropriate projects for partnership with the private sector by public-private partnership contracts. However, this method merely focuses on the direct effects on the project's level and ignores the economic and social impacts and indirect national and regional impacts. This method also is limited to selecting discount rates and tax position adjustments. It ignores both the benefits users receive from increasing the quality of services through public-private partnerships and the project's financing methods. So ignoring these problems can lead to significant errors in assessments. Therefore, the present paper aims to use a complementary approach to make decisions about investing by public-private partnership method in one of the country's infrastructures of water resources development. In this regard, the effect of building, financing, and operation of the desalination project and water transfer from the Persian Gulf to industry and mine sectors in the southeastern provinces of the country by a public-private partnership model and using the recursive dynamic FCGE model to Iran's economic growth simulate and compare it to the traditional procurement model. Based on the results, it has no economic justification if the project is financed in the traditional procurement model (through increasing tax revenues) and financed through public-private partnerships (through the capital market) without increasing the productivity rate. In other words, this project is economically justifiable only if implemented by a public-private partnership contract and increases productivity by at least 0.01% during the operation period. © University of Tehran Abstract.
Publication Date: 2022
Energy Conversion and Management (01968904)269
The photocatalytic fuel cell (PFC) is a combined strategy for pollution removal and energy recovery. Electrochemical and photodegradation properties obtained at the ZnO/ Bi2MoO6/ MIL-101 (Fe)/ FTO photoanode are higher than ZnO/ Bi2MoO6/ FTO and ZnO/ FTO. Open and closed-circuit tests in the PFC system reveal that the closed-circuit has a better removal efficiency. Under optimal conditions (Pollutant concentration = 40 ppm, radiation intensity = 9.25 mW/cm2, pH = 6, irradiation time = 90 min), the removal efficiencies of tetracycline and TOC are 95.1 % and 89.6 %, respectively. The maximum power, short-circuit current, and open-circuit voltage are obtained at 30.58 µW/cm2, 139.2µA/cm2, and 772 mV, respectively. The central composite face-centered (CCF) method is assessed and optimized concerning the process factors effect at optimal conditions. The effect of electrolytes supporting Na2SO4, NaCl, and NaHCO3 electrolytes is evaluated. The NaCl improves the removal efficiency, while the cyclic voltammetry reveals that the current density is better for Na2SO4. For photodegradation and photo electrochemistry, photoanode has good stability after five cycles. © 2022 Elsevier Ltd
Publication Date: 2022
Environmental Science and Pollution Research (09441344)29(40)pp. 61080-61092
The novel quaternary CNT/TiO2/WO3/CdS nanostructure was fabricated to be employed in the photocatalytic degradation of reactive blue 19 (RB19) under the visible light irradiation. The physicochemical properties of the pure TiO2, CNT/TiO2, CNT/TiO2/WO3, and CNT/TiO2/WO3/CdS were characterized using XRD, FTIR, FESEM, EDX, DRS, PL, and BET analyses. The photodegradation results showed that the optimum weight percentage of CNT, WO3, and CdS was 4%, 35%, and 5%, respectively. The highest RB19 degradation efficiency of CNT/TiO2/WO3/CdS was achieved 97%. Besides, the central composite design was applied to model and optimize the photocatalytic activity of CNT/TiO2/WO3/CdS nanocatalyst and assess the effects of processing variables including RB19 concentration, catalyst concentration, pH, and irradiation time on the response. RB19 concentration and pH had the most and the second most significant role in the removal efficiency. While increasing the catalyst concentration and irradiation time positively enhanced the removal efficiency to more than 82%, increasing the pH and dye concentration showed the remarkable hindering effects on the removal efficiency by about 45% reduction. The reusability of the synthesized catalysts was studied under the optimum conditions as follows: [RB19] = 25 mg/L, [catalyst] = 1 g/L, pH of 4, and irradiation time = 2 h. The COD and TOC analyses were also conducted during photodegradation process. The COD and TOC removal efficiencies were achieved about 67% and 62%, respectively. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Publication Date: 2022
Journal of Photochemistry and Photobiology A: Chemistry (18732666)431
A novel Z-scheme Bi2WO6/C3N4/TiO2 ternary heterojunction was successfully synthesized by the sol–gel / hydrothermal method. The photocatalytic activity of Bi2WO6/C3N4/TiO2 was investigated by the phenol degradation under simulated sunlight illumination. The Bi2WO6/C3N4/TiO2 ternary Z-scheme involving 30 wt% of TiO2, while Bi2WO6 to C3N4 mass ratio resulted in 65 to 35, was realized as an optimal composite and exhibited the best photocatalytic activity compared with individual g-C3N4, Bi2WO6/C3N4 and Bi2WO6/C3N4/TiO2 with different mass percentage ratios. The optimum amount of operating parameters were determined as: initial phenol concentration = 10 mg/L, pH = 7, catalyst dose = 1.5 g/L and irradiation time = 180 min. The maximum phenol removal efficiency in the presence of Bi2WO6/C3N4/TiO2 reached 84.7% at optimum conditions. The photocatalytic phenol degradation mechanism followed the first-order kinetic and the reaction rate of the ternary photocatalyst was around 2.18 and 1.34 times, higher than those of Bi2WO6 and Bi2WO6 / C3N4, respectively. In addition, all of the OH●, O2– ●, h+, and e- active species efficiently promoted the photocatalytic process. Complete mineralization took a place almost after 7.5 h from the beginning of the phenol photodegradation the synthesized Z-scheme exhibited excellent chemical constancy and reusability next to the five cycles of utilizations. © 2022 Elsevier B.V.
Mahmoudi n., ,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Eskandari, P.,
Esfahani k.n., Publication Date: 2022
International Journal of Environmental Science and Technology (17351472)19(3)pp. 1671-1682
Abstract: This study investigates the decolorization of two widely used textile dyes (Acid Black 172 (AB172) and Disperse Blue 56 (DB56) by using a combined sono-photo-electro-Fenton (SPEF) process. The effects of dye structure and processing factors on dye degradation from contaminated water and COD removal efficiency were determined by adopting response surface methodology. The results confirmed that current density, irradiation time, pH, H2O2C0, and AB172 concentration had the most impacts on COD removal, respectively, whereas DB56 removal efficiency was highly dependent on the initial dye concentration and H2O2C0, compared to other processing factors. The dye degradation efficiency of 95.5% and COD removal efficiency of 91.6% for DB56 were obtained at optimum conditions of pH = 3, current density = 2 mA.cm−2, dye concentration = 200 ppm, H2O2C0 of 0.78 and irradiation time of 30 min. In the case of AB172, the same optimum conditions were found unlike reaction time of 50 min and H2O2C0 of 0.33, which resulted in the optimal dye degradation efficiency and COD removal of 97.4% 94.5%, respectively. These results verified that the type of dye and its structure can be a key factor in the Fenton-based degradation process. The comparison of the performance of different Fenton-based processes confirmed that the removal efficiency of electro-Fenton, sono-electro-Fenton, photo-electro-Fenton, and SPEF was 82–88%, 89.5–91%, 91.5–92.3% and 95.5–97.4%, respectively. The Fenton-based processes are highly effective methods that can be applied for water and wastewater treatment. Graphic Abstract: [Figure not available: see fulltext.] © 2021, Islamic Azad University (IAU).
Publication Date: 2022
Applied Surface Science (01694332)602
The new ZnO nanorods/ Bi2MoO6/ MIL-101(Fe) photocatalyst is synthesized by applying the solvothermal method and is characterized by XRD, FTIR, SEM, EDX, TEM, UV–vis DRS, PL, BET, and TGA analyses. The optimal molar composite ratio is ZnO: Bi2MoO6: MIL-101(Fe) = 2: 1: 0.52 with a 2.3 eV bandgap which has significantly enhanced photocatalytic activity observed in visible light irradiation (420 nm) for tetracycline degradation. The type-II/type-I heterojunction is applied for the photocatalyst reaction mechanism based on the experimental data concerning pollutant concentration = 20 ppm, catalyst dosage = 0.38 g/L, pH = 7, irradiation time = 90 min, optimum conditions, tetracycline removal efficiency, and TOC at 96.1 and 87.4%, respectively. The catalyst is immobilized on the FTO glass by applying the spin coating method, where tetracycline removal efficiency and TOC are obtained at 91.7% and 84.7%, respectively. The toxicity test is run by applying the growth of Escherichia coli (E. coli) bacteria and confirms the non-toxicity of the intermediate products during the photocatalytic process. © 2022 Elsevier B.V.
Publication Date: 2022
Journal of Environmental Management (10958630)316
ZnO nanorod along with a Zn2TiO4/GO heterostructure with enhanced charge transfer capability was synthesized by a facile sol-gel method. FT-IR, XRD, XPS, TEM, SEM, EDX, UV–Vis DRS, photocurrent response and PL analyses were applied to characterize the as-prepared photocatalysts. To investigate the photocatalytic activity of the composite, Cefixime (CEF) removal under visible light was evaluated. The ZnO nanorod/Zn2TiO4/GO, including 65 wt% ZnO and 3 wt% graphene oxide, showed the highest CEF degradation and was selected as the optimal ternary composite. Reduction of electron-hole pair recombination rate, successful interfacial charge transfers, and more visible light reception in the Z-scheme system were the important reasons for improving the photocatalytic properties of ZnO nanorod/Zn2TiO4/GO. Effective operating parameters in the CEF photocatalytic removal process were optimized employing the response surface method and were as follows: photocatalyst dosage = 0.88 g/L, pH = 5, radiation time = 115 min, and CEF concentration = 10 ppm. The photocatalytic degradation% of CEF and total organic carbon (TOC) removal% under the optimal conditions were 71.4 and 57.5%, respectively, for the three-component composite indicating the production of intermediate species during the process. This photocatalytic reaction confirmed the first-order kinetic and using the ZnO nanorod/Zn2TiO4/GO composite was able to improve the reaction rate by about 2.7 and 6.2 times more than ZnO nanorod/Zn2TiO4 and ZnO, respectively. The effects of radiation intensity and temperature were investigated and 175 W/m2 and 35 °C were obtained as optimum values. Eventually, according to the trapping test, h+, superoxide radical, and hydroxyl radical are the most effective active species in this photocatalytic reaction, respectively. © 2022 Elsevier Ltd
Mokhtari n., ,
Solaimany nazar a.r., A.R.,
Farhadian, M.,
Eskandari, P.,
Jeon, B. Publication Date: 2022
International Journal of Environmental Science and Technology (17351472)19(12)pp. 12465-12476
The development of visible light-responsive metal-doped TiO2 for the treatment of water and wastewater has gained much attention. Herein, TiO2/Ag nanocatalyst thin films stabilized on glass was successfully obtained by a simple sol–gel method. The morphology, crystalline and functional structure, bandgap energy, and optical properties of synthesized TiO2/Ag were studied by XRD, FTIR, FESEM-EDX, and UV–Vis DRS analyses. The results showed that the size of most of the nanoparticles was between 20 and 40 nm. Besides, the red shift to the visible region and the reduction of bandgap energy to 2.7 eV were observed as a result of the modification of TiO2 by Ag. The diphenhydramine (DPH) and venlafaxine (VNF) photodegradation efficiency were studied using the TiO2/Ag/UV–Vis process with independent variables by the response surface methodology (RSM). The proposed RSM models with high R2 (0.996–0.997) confirmed a satisfactory correlation between the experimental results and predicted values. The RSM results showed the significant inhibitive effects of increasing antibiotic concentration on the removal efficiency, whereas the highest positive impacts on the degradation efficiency were obtained by increasing the irradiation time. More than 70% of drugs were removed under optimum conditions (20 mg/L of initial VNF (DPH) concentration, pH of 10 under 180 min illumination). © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.
Publication Date: 2022
Advanced Powder Technology (15685527)33(5)
The integration of Bi2MoO6 with MIL-101(Fe) as a novel structure enhanced photocatalytic activity for RhB degradation. Bi2MoO6/MIL-101(Fe) composites were synthesized via the solvothermal procedure and characterized by XRD, EDX, FE-SEM, TEM, FT-IR, BET, TGA, UV–vis DRS, and PL. The optimal molar ratio Bi2MoO6:MIL-101(Fe) equal to 1:1 showed better photocatalytic activity than Bi2MoO6 and MIL-101(Fe) and other heterostructure composites. The effect of pH (5–9), reaction time (60–120 min), catalyst concentration (0.1–0.5 g/L), and dye concentration (10–20 ppm) were investigated on the removal performance of RhB by using central composite face-centered (CCF). In the optimal process factors where the [Catalyst]:0.4 g/L, [RhB]:20 ppm, pH: 6.5, irradiation time: 120 min, the RhB and TOC removal efficiency were 85% and 84.2%, respectively. The holes and superoxide radicals played a major role in the degradation of RhB. The addition of salt (NaCl, Na2SO4, and NaHCO3) at different concentrations (100, 200, 400, and 800 ppm) revealed that the salts have an inhibitory role in the photocatalytic performance. At low concentrations of 100 ppm, the salts had a negative effect on removal efficiency (kPure water = 0.0155 min−1, kNaCl = 0.0075 min−1, kNa2SO4 = 0.0132 min−1, kNaHCO3 = 0.006 min−1). Increasing the salt concentration to 800 ppm caused improved efficiency for NaCl (kNaCl = 0.0141 min−1), while for Na2SO4 this trend was decreasing (kNa2SO4 = 0.011 min−1), and for NaHCO3 sharply diminished (kNaHCO3 = 0.0026 min−1). © 2022 The Society of Powder Technology Japan
Publication Date: 2022
Process Safety and Environmental Protection (17443598)164pp. 747-760
A Bi2O3/ZIF-67 heterostructure was synthesized as a novel and highly active photocatalyst by the hydrothermal method. The as-synthesized catalysts were identified by XRD, SEM, EDX, FTIR, TEM, UV–Vis DRS, BET, and PL analyses. The two-component composite showed a significant improvement in photoactivity compared to Bi2O3 and pristine ZIF-67 due to its unique characteristics such as increased specific surface area and visible light adsorption, as well as reduced bandgap and recombination rate of electron-hole. The optimum values of the processing variables for the contaminant degradation efficiency were determined for photocatalytic process (catalyst concentration= 0.4 g/L, pH= 9, tetracycline (TC) initial concentration= 20 mg/L, and time= 120 min) and capacitive deionization system (CDI) (L=5 mm, voltage=1.8 V, and TC concentration=20 mg/l) and the maximum pollutant removal efficiency under optimal conditions for catalyst adsorption, photocatalytic process, and CDI systems were obtained 12%, 84% and 69%, respectively. The identification of a kinetic study confirmed that the TC removal followed the pseudo-first-order model. According to kinetic studies, the combination of photocatalysis and CDI system (PCS) has a significant effect on the efficiency of the contaminant removal, and the reaction rate constant is increased by about 1.5 and 2.4 times compared to the photodegradation process and the CDI system, respectively. As the results show, the PCS system is a promising way of removing contaminants and dramatically increasing the removal efficiency. Experimental results showed a great chemical stability and reusability of the photocatalyst and the graphite electrode after five cyclic usage. © 2022
Publication Date: 2022
Environmental Science and Pollution Research (09441344)29(16)pp. 24286-24297
In this study, pristine MIL101(Cr) was modified to synthesize hydroxyl-functionalized (MIL101(Cr)-OH) and chitosan (CS)-coated (MIL101(Cr)-OH/CS) metal-organic frameworks (MOFs) to enhance adsorption capacity and reusability, respectively. The synthesized adsorbents were characterized by XRD, FTIR, and BET analyses. The kinetics behavior and the equilibrium adsorption of diphenhydramine (DPH) and metronidazole (MNZ) from aqueous solution on the synthesized adsorbents and a commercial activated carbon were compared at 25°C. The pH-dependent of the adsorption capacity and reusability of MIL101-OH/CS were investigated. The results showed that upon adding OH functional group and chitosan polymer, the adsorption capacity increased; the DPH adsorption capacity on MIL101-OH and MIL101-OH/CS was 634 and 573 mg/g, respectively. Also, the maximum adsorption capacity of MNZ on MIL101-OH/CS was 600 mg/g, which was twice the adsorption capacity of MIL101 and four times the adsorption capacity of the commercial activated carbon. The equilibrium and kinetics behavior results were in good agreement with Langmuir and the pseudo-second-order models, respectively. The DPH and MNZ adsorption mechanisms on MIL101-OH/CS were hydrogen bonding and electrostatic interactions, respectively. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Publication Date: 2021
Scientia Iranica (23453605)28(3)pp. 1464-1477
This study aims to remove one of the frequently used dyes in textile industries, i.e., Methyl Orange, from polluted water with TiO2/ZnFe2O4/glycine catalyst under UV irradiation. The TiO2/glycine/ZnFe2O4 nanocatalyst was synthesized using the sol-gel method and characterized by XRD, XRF, FT-IR, UV-visible DRS, BET, FE-SEM, and EDX analyses. Process factors including initial dye concentration (10-30 ppm), catalyst dosage (0.5-1.5 g/L), initial pH solution (3-11), and irradiation time (30-150 min) were investigated by central composite design. The removal efficiency of methyl orange was 80% under the optimal conditions, i.e., dye concentration of 20 ppm, catalyst dosage of 1 g/L, irradiation time of 120 min, and pH = 6.5. The effects of mineral salts such as NaHCO3, NaCl, Na2SO4c, KCl, MgSO4, and CaCl2 with the concentrations of 50-800 ppm on the dye removal efficiency were evaluated under optimal conditions. Although low concentrations of NaCl, KCl, and CaCl2 had adverse effects on MO removal efficiency, the dye removal efficiency was enhanced at their high levels (RNaCl.800 = 74:52%). An increase in the concentrations of MgSO4 and Na2SO4 produced deactivation effects on the dye removal efficiency and reaction rate constant (MgSO4 deactivation: 36%). The pollutant removal efficiency and reaction rate constant increased using NaHCO33 (RNaHCO3.800 = 82:4% and kNaHCO3.800 = 20:84 day-1). © 2021 Sharif University of Technology. All rights reserved.
Publication Date: 2021
International Journal of Environmental Science and Technology (17351472)18(2)pp. 297-316
Nanocrystalline metal oxides including TiO2, Fe2O3, and ZnO and their combinations were impregnated on activated carbon (AC) and characterized by XRD, FTIR, and FESEM analyses. The results showed the size of most Fe2O3/AC, TiO2/AC, TiO2/Fe2O3/AC, ZnO/AC, and ZnO/Fe2O3/AC particles are in the range of 25–60 nm. BET analysis verified the high surface area of the six adsorbents (201–448 m2/g). The adsorption results confirmed that the modification could improve the adsorption capacity and removal efficiency as the maximum monolayer adsorption capacity and cyanide removal efficiency were observed for ZnO/Fe2O3/AC (101.0 mg/g, 82.5%), TiO2/Fe2O3/AC (96.2 mg/g, 75.1%), ZnO/AC (91.7 mg/g, 73.5%), TiO2/AC (90.9 mg/g, 72.4%), Fe2O3/AC (86.2 mg/g, 69.2%,), and AC (78.1 mg/g, 66.3%), respectively. Moreover, the study of different isotherm models including Langmuir, Freundlich, and Redlich–Peterson indicated that the Langmuir model was the most suitable one for the six adsorbents with 0.56 < RL < 0.64. The kinetic modeling of experimental data revealed the cyanide adsorption on all adsorbents followed the pseudo second-order model confirming chemisorption can be a main mechanism of adsorption. The regeneration and reusability results showed modified AC adsorbents have more reusable and stable structure than AC to be used as adsorbents in industrial wastewaters. The performance of adsorption process was compared with different methods of cyanide removal. The results approved that adsorption process as a cost-effective and simple design method using bioadsorbents can be highly effective in full-scale applications for the removal of high concentration of cyanide. © 2020, Islamic Azad University (IAU).
Publication Date: 2021
Applied Physics A: Materials Science and Processing (14320630)127(10)
Metronidazole (MTZ) is an antibacterial drug, which is frequently detected in wastewater, resulting in pathogen-resistance and mutagenicity. Therefore, MTZ removal is a serious challenge. In this research work, the visible-light-driven Z-scheme CuWO4/Bi2S3 heterojunction with optimized weight percentage (7%wt) was evaluated for MTZ degradation under LED radiation in batch and continues reactor. The effect of operational factors such as MTZ concentration (10–30 ppm), catalyst dose (0.4–1 mg/L), pH (3–9) and illumination time (90–150 min) on MTZ degradation efficiency was investigated through response surface methodology (RSM). The optimum values of the operating parameters were found to be as: irradiation time = 150 min, pH = 3, MTZ concentration of 10 ppm and catalyst dose = 0.7 g/L. The utmost degradation efficiencies were obtained 79% and 84%, respectively, in batch and continues flow mode at the optimum conditions. Thereafter, the effect of immobilization of the binary composite on FTO was studied at the obtained optimum conditions. The effect of temperature and light intensity on photocatalytic performance was also investigated, and the optimal values were found to be 25 °C and 400 W/m2, respectively. The mineralization of MTZ was investigated through TOC removal rates with the maximum value of 61.32%. The gas chromatography-mass spectrometry analysis was used to detect the photodegradation intermediates. The kinetic study of MTZ degradation by the binary composite followed the pseudo-first order by the reaction rate of 2 times greater than pristine Bi2S3. The main active species were found to be hydroxyl radical and superoxide by the trapping test method. The binary heterojunction demonstrated high durability and stability after five cycles. This work recommends a promising heterojunction for MTZ photodegradation. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.
Publication Date: 2021
Journal of Molecular Liquids (18733166)339
A Z-scheme Bi2WO6/CNT/TiO2 heterostructure was synthesized through the hydrothermal method. The photocatalysts were characterized by XRD, FTIR, SEM, EDX, TEM, UV–vis DRS, PL, and BET-BJH analyses. The photocatalytic activity of Bi2WO6/CNT/TiO2 was evaluated by the degradation of cephalexin under simulated sunlight illumination. The ternary Bi2WO6/CNT/TiO2 Z-scheme containing the optimal loading amount of 35 wt% TiO2 and 0.75 wt% CNTs, showed the best photocatalytic activity compared with pristine Bi2WO6, Bi2WO6/TiO2 and Bi2WO6/CNT/TiO2 with different mass percentage ratios. The enhanced photocatalytic activity of Bi2WO6/CNT/TiO2 was attributed to the higher specific surface area, higher visible-light adsorption spectrum, lower band gap, lower recombination of electron-hole pairs, better charge separation and higher redox ability, due to the Z-scheme construction. The optimum values of operating parameters were determined as: catalyst dose = 0.75 g/L, pH = 5, illumination time = 70 min, and cephalexin initial concentration = 20 mg/L using the central composite design. The maximum cephalexin removal efficiency in the presence of Bi2WO6/CNT/TiO2 reached 89.7% at optimum conditions. The maximum total organic carbon (TOC) removal rate was 78.9%. The photocatalytic degradation of cephalexin followed the first-order kinetic and the reaction rate by ternary composite was about 3.33 and 1.5 times, greater than those of Bi2WO6 and Bi2WO6/TiO2, respectively. The synthesized Z-scheme demonstrated an excellent chemical stability and reusability after five cyclic utilizations. According to matched Fermi level of CNTs between Bi2WO6 and TiO2, CNTs acted as electron mediator for charge transfer in the Z-scheme. Assigned to the trapping experiments, OḢ, O2−•, h+ and e- effectively improved the photodegradation process. © 2021 Elsevier B.V.
Publication Date: 2021
Materials Science in Semiconductor Processing (13698001)127
A novel Z-scheme MnWO4/Bi2S3 heterojunction was constructed by a hydrothermal method for the first time. The structure, morphology and optical absorption characterization of photocatalysts were comprehensively identified. The photocatalytic performance of catalysts was investigated by the cephalexin (CFX) and metronidazole (MTZ) degradation under LED irradiation. The degradation efficiency of binary composite was promoted compared to pure MnWO4 and Bi2S3. The enhanced performance was assigned to the Z-scheme construction, leading the broad visible-light adsorption spectrum, superior redox potential as well as impressive separation and reduced recombination of photo-induced charge carriers. The effect of catalyst dose, temperature and light intensity on photodegradation activity was studied. The effect of inorganic ions was investigated in order to simulate the actual situation. The optimal values of catalyst dose, temperature and illumination intensity were found to be 1.2 g/L, 25 °C and 400 W/m2, respectively. The maximum degradation efficiencies of 74.5% and 79.8% were achieved for CFX and MTZ, respectively. TOC removal analysis was applied to measure the mineralization of CFX (46%) and MTZ (65.2%). The degradation intermediates were distinguished by using the gas chromatography/mass spectrometry (GC/MS) analysis. The kinetic investigation of photodegradation followed the first order kinetic for both drugs. The novel binary composite depicted high stability after six cycles. The trapping experiments detected the hydroxyl (OH.) and superoxide (O2.) radicals as the main active species. This research revealed a novel Z-scheme photocatalyst as a promising strategy in order to remove antibiotics. © 2021
Publication Date: 2021
Journal of Applied Electrochemistry (15728838)51(10)pp. 1387-1405
Abstract: This study aimed to degrade the two most commonly used dyes in textile industries, Acid Black 172 and Reactive Blue 19, in pollutant water via Photoelectro-Fenton-like and Photoelectro-Fenton-like/Photocatalyst processes under visible-light irradiation. Graphite and copper plates were used as cathode and anode electrodes, respectively. Suspended TiO2/glycine/ZnFe2O4 photocatalyst was synthesized through the sol–gel method, and the stabilization of TiO2/glycine/ZnFe2O4 photocatalyst on graphite cathode was conducted via dip-coating method. The synthesized photocatalyst was characterized by X-ray diffraction, X-ray fluorescence, Fourier-transform infrared spectroscopy, ultraviolet–visible diffuse reflection spectroscopy, photoluminescence, Brunauer–Emmett–Teller, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy analyses. Initial dyes concentration, current density, initial pH solution, and irradiation time were investigated by response surface methodology. The results indicated that Acid Black 172 degradation efficiency increased from 72% in Photoelectro-Fenton-like process to 92% in Photoelectro-Fenton-like/immobilized photocatalyst process with 1 g L−1 TiO2/glycine/ZnFe2O4 photocatalyst under the optimal conditions (Acid Black 172 concentration = 200 mg L−1, pH 6.5, irradiation time = 46 min, and current density = 2 mA cm−2). There was also a 15% increase in Reactive Blue 19 degradation efficiency in Photoelectro-Fenton-like/immobilized photocatalyst process using 1 g L−1 TiO2/glycine/ZnFe2O4 photocatalyst under the optimal conditions (Reactive Blue 19 concentration = 196 mg L−1, pH 6.5, irradiation time = 30 min, and current density = 2.7 mA cm−2). Graphic abstract: [MediaObject not available: see fulltext.].s © 2021, The Author(s), under exclusive licence to Springer Nature B.V.
Asadpoor, M.,
Arjmand m., ,
Farhadian, M.,
Omidkhah, M.,
Zinatizadeh, A.A. Publication Date: 2021
Desalination and Water Treatment (19443994)209pp. 219-229
In this work, the photocatalytic degradation of Acid black 1721 (AB1721) in the presence of a novel photocatalyst (TiO2 – titanium dioxide) TiO2 /CNT/BiOBr/Bi2 S3 under visible light irradiation was investigated. The effect of different loadings of carbon nanotubes (CNT) (1%, 2%, 4%, 6% and 8%), BiOBr (10, 20, 30 and 40 wt.%) and Bi2 S3 (5, 10, 15 and 20 wt.%) on the photocatalytic activities of the prepared nanocomposites was investigated. The structural properties of the nanocomposites have been characterized by X-ray diffraction, Brunauer–Emmett–Teller, diffuse reflectance spectra (DRS), Field-emission scanning electron microscopy, photoluminescence spectroscopy (PL) and Fouriertransform infrared spectroscopy. The results show that the photodegradation efficiency of TiO2 /4CNT/20-BiOBr/10-Bi2 S3 photocatalyst was better than the samples. Results of DRS show a visible shift when TiO2 /CNT was modified with BiOBr and Bi2 S3. Also, PL spectra for all the prepared samples indicated that TiO2 /4-CNT/20-BiOBr/10-Bi2 S3 had the lowest recombining of electron and holes. The effect of independent variables including initial dye concentration (30, 60 and 90 mg/L), pH (3, 6 and 9), irradiation time (20, 30 and 40 min) and catalyst loading (0.5, 0.75 and 1 g/L) on dye removal was determined by response surface methodology. The optimum condition was AB1721 concentration of 30 mg/L, initial pH of 3, the reaction time of 40 min, and catalyst loading of 1 g/L. © 2021 Desalination Publications. All rights reserved.
Publication Date: 2021
Environmental Nanotechnology, Monitoring and Management (22151532)15
TiO2/BiOBr/Bi2S3 nanostructure impregnated on the activated carbon (AC) was synthesized, in order to achieve considerable synergy between photocatalysis and adsorption for 2,4-dichlorophenoxyacetic acid (2,4-D) removal from polluted water. The XRD, XRF, EDX, FE-SEM, and FT-IR analyses confirmed successful formation of the catalyst. The results of UV-DRS analysis, showed the estimated band gaps obtained were about 2.8 eV and 2.55 eV for the TiO2/BiOBr and TiO2/BiOBr/Bi2S3 nanostructures respectively showing high potential for the wide range of visible and solar spectrum. The photocatalytic degradation results based on the response surface methodology (RSM) experimental design confirmed that initial 2,4-D concentration, pH, catalyst concentration, irradiation time and the interaction between TiO2/BiOBr/Bi2S3/AC concentration and irradiation time had the most effects, respectively. The best results were obtained under the optimum conditions (2,4-D = 90 mg/L, pH = 3, catalyst = 0.6 mg/L and irradiation time = 90 min) on which the pollutant removal efficiency was 98 % and TOC removal efficiency was determined 74 %. Increasing the visible light intensity to 120 mW/cm2 resulted in a complete degradation. The coexistence of 10 % BiOBr and 5%Bi2S3 compounds on TiO2 not only increased the absorption edge to 600 nm and charge transportation but also improved photocatalytic properties of TiO2/BiOBr/Bi2S3/AC nanostructure as it could be an appropriate compound for water treatment. © 2020 Elsevier B.V.
Rabanimehr, F.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Behineh, E.S. Publication Date: 2021
Journal Of Applied Research In Water And Wastewater (24766283)8(1)pp. 36-40
In photocatalytic microreactors the catalyst layer is obtained by integration of nanostructure films of semiconductors. One of these nanostructures that have a good photocatalytic activity is ZnO nanowires. The photocatalytic degradation of methylene blue in a continuous flow microreactor with ZnO nanowires deposited film is simulated. A finite element model is developed using COMSOL Multiphysics version 5.3 software to simulate the microreactor performance. The kinetic law of the photocatalytic reaction is assumed to be Langmuir–Hinshelwood. The kinetic constants kLHa and K are determined 1.43 × 10-7 mol/m2s and 7.5 m3/mol, respectively. The percent of average absolute deviation of the model in predicting the methylene blue outlet concentration obtained about 0.12% mol/m3. The model showed a very good agreement with the published experimental data. The effect of microreactor depth, methylene blue inlet concentration and flow rate on the methylene blue degradation is also investigated. The simulation results showed that the microreactor with shorter depth and lower values of inlet concentration and flow rate has higher efficiency. Thiele modulus and Damköhler number are both estimated lower than 1. It indicates that the photocatalytic reactions occur without internal and bulk mass transfer limitations. © The Author(s).
Publication Date: 2021
Environmental Technology (United Kingdom) (1479487X)42(11)pp. 1734-1746
ZnO/Fe2O3/Clinoptilolite photocatalyst was synthesized through sol–gel method. The photocatalyst was characterized by XRD, XRF, EDX, FE-SEM, FT-IR, BET and UV–VIS DRS analyses. According to the XRD, FT-IR, and EDX results, the presence of ZnO and Fe2O3 was confirmed on the clinoptilolite surface. Based on the XRF results, the molar ratio of Fe3+/ZnO in the photocatalyst was obtained as 0.06. The FE-SEM results confirmed stabilization of ZnO/Fe2O3 on the clinoptilolite surface. Based on the BET results, the surface area and pore volume for the photocatalyst were obtained as 291.35 m2/g and 0.23 cm3/g, respectively. According to the UV–VIS DRS results, the band gap energy of the photocatalyst was measured as 3.38 eV. The performance of the synthesized photocatalyst in degrading metronidazole from contaminated water, as one of the most widely used antibiotics in pharmaceutical industries, was evaluated by response surface methodology. Operational factors including pH (4–10), metronidazole concentration (1–100 mg/l), irradiation time (45–180 min), photocatalyst concentration (0.5–2 g/l), and H2O2 concentration (25–100 mg/l) were investigated. The optimal values of the factors in degrading 99% of the contaminant were as follows: irradiation time = 90 min, photocatalyst concentration = 1 g/l, pH = 10, H2O2 concentration = 40 mg/l, and MNZ concentration = 60 mg/l. © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Asadpoor, M.,
Ardjmand, M.,
Farhadian, M.,
Omidkhah, M.,
Zinatizadeh, A.A. Publication Date: 2021
Chemical Papers (03666352)75(3)pp. 1267-1278
In present study, new visible driven photocatalysts (TiO2/4-CNT/20-BiOBr/10-Bi2S3) with various loading of CNT (2, 4, 6 and 8 wt%), (10, 20, 30 and 40 wt%) and Bi2S3 (5, 10, 15 and 20 wt%) were successfully synthesized and characterized by XRD, FTIR, FESEM, PL, and DRS analysis. The DRS and PL analysis confirmed a redshift of modified TiO2 into a visible light range and the reduction of the recombination rate of electron/hole. The photodegradation results showed the optimum weight percentage of CNT, BiOBr, and Bi2S3 was 4%, 20%, and 10% respectively. Besides, the central composite design (CCD) was applied to model and optimize the photocatalytic activity of nanocatalyst for photodegradation of reactive blue 19 (RB19) and assess the effects of four independent variables including RB19 concentration, catalyst concentration, pH, and irradiation time on the response. The photocatalytic activity performance of TiO2/4-CNT/20-BiOBr/10-Bi2S3 under visible light irradiation for RB19 removal showed that 97.2% dye removal efficiency was obtained at optimum conditions of pH 4, catalyst dosage 1 g/L, RB19 concentration 50 mg/L, and contact time 60 min. The investigation of the effect of processing factors on the dye removal efficiency confirmed that increasing the catalyst concentration and time while decreasing pH and dye concentration resulted in the dye removal efficiency in a short time. The reusability of the catalyst was studied under optimum conditions ([RB19] = 50 mg/L, [TiO2/4-CNT/20-BiOBr/10-Bi2S3] = 1 g/L, pH = 4 and irradiation time = 60 min). © 2020, Institute of Chemistry, Slovak Academy of Sciences.
Publication Date: 2020
Applied Surface Science (01694332)505
A ternary heterojunction of Cu2S/Ag2S/BiVO4 with enhanced charge transfer ability was synthesized via hydrothermal method and stabilized on the α-Al2O3 fiber. Catalysts were characterized by XRD, XRF, FT-IR, BET-BJH, FE-SEM, EDS, pHzpc, UV–Vis DRS, and PL spectra. Compared with pure BiVO4, at the optimal operational condition with 50 mg/l of metronidazole, 1 g/l of catalyst, irradiation time of 105 min, and at pH = 3, the degradation of contaminant was obtained as 52, 74.7, 85.8, and 94.5% by BiVO4, 5 wt% Ag2S/BiVO4, 15 wt% Cu2S/Ag2S/BiVO4, and 15 wt% Cu2S/Ag2S/BiVO4@α-Al2O3 respectively. The significant increment of photocatalytic activity of Cu2S/Ag2S/BiVO4 was related to the higher specific area, synergistic interfacial charge transfers, and promotion of electron-hole pair separation in the dual Z-scheme system. The α-Al2O3 acts as a photo-generated charge trapper which restrains the recombination of electron-hole pairs. The presence of α-Al2O3 drastically reduced the PL intensity of Cu2S/Ag2S/BiVO4. According to the quenching experiments, a reasonable mechanism of Cu2S/Ag2S/BiVO4 was also proposed. The effects of temperature and light intensity were also tested and the optimal values were determined at 25 °C and 400 w/m2 respectively. In the continuous system, at the optimum flow rate (2.4 ml/min), metronidazole degradation was 96.2% by Cu2S/Ag2S/BiVO4@α-Al2O3. © 2019 Elsevier B.V.
Publication Date: 2020
Chemosphere (00456535)251
A novel double Z-scheme CuWO4/Bi2S3/ZIF67 ternary heterostructure was synthesized through hydrothermal method. The catalysts were characterized by XRD, FTIR, SEM, EDX, BET, TEM, PL, and UV–vis DRS analyses. The degradations of Metronidazole (MTZ) and Cephalexin (CFX) antibiotics by ternary catalyst were investigated in the batch and continuous slurry photoreactor under LED illumination. The ternary heterostructure exhibited a remarkable improvement in photoactivity compared with CuWO4/Bi2S3, and pristine ZIF67. Indeed, higher surface area, photo-stability, bandgap suppressing as well as better charge separation based on the dual Z-scheme structure caused the enhancement. The optimum values of operating parameters were obtained by the central composite design as: catalyst dose = 0.3 g/L, pH = 7, illumination time = 80 min, and 20 ppm initial concentration of antibiotic. The maximum degradation efficiencies by the new ternary heterostructure were 95.6% and 90.1%, respectively for MTZ and CFX at optimum conditions in the continuous flow mode. Maximum total organic carbon (TOC) removal rates were 83.2% and 74% for MTZ and CFX, respectively. The degradations by ternary composite followed the first-order kinetic, by reaction rate of 9 times, 5.5 times, and 4 times higher than that obtained by Bi2S3, ZIF67, and the binary CuWO4/Bi2S3, respectively. The influences of temperature and light intensity were explored, revealing 25 °C and 400 W/m2 as the optimum values. The new ternary heterostructure demonstrated excellent reusability and chemical stability after six cycles. The dominant active species were explored by trapping tests, indicating OH. free radicals as the most primary oxidant. © 2020
Aram, M.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Tangestaninejad, S.,
Eskandari, P.,
Jeon, B. Publication Date: 2020
Journal of Molecular Liquids (18733166)304
Cephalexin (CEX) and metronidazole (MNZ) degradation were photodegraded using the synthesized Urea/TiO2/ZnFe2O4/-Clinoptiloite catalyst under visible light irradiation. Diffuse reflectance ultraviolet–visible spectroscopy (UV–Vis DRS) and photoluminescence (PL) analysis approved the modification of TiO2 by Urea and ZnFe2O4 compounds increased the absorption edge of catalyst to 590 nm and decreased the electron−hole recombination rate. The results showed the degradation efficiencies of ozonation process for the metronidazole and cephalexin removal were obtained 36% and 39%, respectively. The photocatalyst activity of Urea/TiO2/ZnFe2O4/Clinoptiloite(Zeolite) under visible light irradiation was determined 70% for metronidazole and 74% for cephalexin degradation. Furthermore, the combination of ozonation process and photocatalyst degradation under visible light irradiation showed high potential for the antibiotics degradation (94% for metronidazole and 95% for cephalexin) due to the increase in the generation of reactive species and synergistic effect between photocatalysis and ozonation processes. The response surface methodology (RSM) results revealed the removal efficiency of both pollutants were highly dependent on pH, irradiation time, catalyst concentration and initial antibiotics concentration. First order kinetics model descripted the degradation process and the rate constants were 0.0196 and 0.0243 min−1 for the metronidazole and cephalexin removal, respectively. © 2020 Elsevier B.V.
Publication Date: 2020
Journal of Environmental Chemical Engineering (22133437)8(5)
The Z-scheme Ag2S/BiVO4@α-Al2O3 heterojunction was prepared successfully via hydrothermal method. The as-synthesized catalysts were characterized through different analyses. The photocatalytic activity of the catalysts was examined based on metronidazole degradation under visible light irradiation in batch and continuous photo-reactor (BPR and CPR). The highly effective role of α-Al2O3 substrate in the performance of the powdered catalyst was evaluated. Under the optimum operating conditions in BPR the removal efficiency of metronidazole (10 mg/L) was obtained as 11.2, 49.6, 81.6, and 90.5% by Ag2S, BiVO4, 5 wt% Ag2S/BiVO4 and 5 wt% Ag2S/BiVO4@α-Al2O3 respectively. The considerable improvement of the photocatalytic performance of pure catalysts could be ascribed to the higher specific area, accelerated interfacial charge transfer, remarkable reduction of PL intensity and prolonged life time of electron-hole pairs in composites. Further, in CPR, the maximum photo-degradation of 10 mg/L of MNZ, rhodamine B, tetracycline and sulfamethoxazole were observed as 92.2, 98.5, 93.7 and 82.5% respectively, while the flowrate was kept at 2.8 ml/min. The effects of water matrix as well as different cations and anions were also examined on metronidazole degradation. In the tap water, the degradation efficiency and mineralization of metronidazole were obtained as 78 and 63% respectively after 180 min. © 2020 Elsevier Ltd.
Publication Date: 2020
Journal of Environmental Chemical Engineering (22133437)8(1)
The N and C-N doped TiO2-CuO nanocomposites with different loadings of urea (25, 40 and 50 wt. %), l-Asparagine (0.5-2.5 wt. %) as dopants and CuO (5-25 wt. %) were synthesized and their optimum composition characterized using different analyses such as XRD, FTIR, DRS, FESEM, and PL analyses. The photodegradation results showed that urea with a TiO2 to urea mass ratio of 3:2, l-Asparagine and CuO with a weight fraction of 2 and 10 % were the optimum amounts of the modifiers in the prepared nanocomposites. The C-N codoped TiO2-CuO indicates the highest photocatalytic activity for Direct red 16 (DR16) as azo dye compared to the other modified nanocomposites. The DR16 photodegradation efficiency of C-N codoped TiO2-CuO nanocomposite was also studied with four variables (DR16 concentration, photocatalyst concentration, initial pH and irradiation time) by central composite design (CCD). Experimental data showed that the pH of the solution has a considerable hindering effect on the dye removal efficiency while the role of photocatalyst concentration is minor in comparison with the other variables. Increasing DR16 concentration and initial pH of solution reduces dye removal efficiency. The photocatalyst concentration improves the photodegradation performance slightly but showed an inhibitory effect at photocatalyst concentration higher than 1.5 g/L. It must also be noted that irradiation time had a remarkable positive impact on the photocatalyst process. DR16 was completely removed at optimum conditions (25 ppm of DR16, 1.5 g/L of C-N codoped TiO2-CuO, pH of 4 after 120 min). © 2020 Elsevier Ltd. All rights reserved.
Publication Date: 2020
Journal of Photochemistry and Photobiology A: Chemistry (18732666)394
Herein, a new visible-light driven CuWO4/Bi2S3 Z-scheme composite was synthesized by a hydrothermal method. The photocatalyst was specified by XRD, FT-IR, EDX, SEM, TEM, HRTEM, BET, UV–vis DRS and PL analyses. The prepared heterojunction greatly improved the CFX photodegradation performance compared with pristine Bi2S3 and CuWO4 under LED illumination. The enhanced degradation efficiency was assigned to the higher visible-light adsorption spectrum, higher redox ability, effective separation and reduced recombination of photoinduced electron-hole pairs due to the Z-scheme construction. The point of zero charge (pzc) pH for the binary CuWO4/Bi2S3 heterojunction was calculated as 6.2 through pH drift method. The maximum degradation efficiencies in batch (76 %) and continoues flow (81.7 %) reactor were achieved at optimum values of the operating parameters as follows: irridation time = 150 min, CFX concentration = 10 ppm, pH = 3 and 0.8 g/L of catalyst dose. The optimum values for temperature and light intensity were 25 °C and 400 W/m2, respectively. According to the kinetic studies, the photocatalytic degradation of CFX followed the first order kinetic. The new Z-scheme composite indicated desirable reusability and chemical stability after five cycles. According to the trapping tests, the Z-schematic construction was proposed for the photocatalytic mechanism and superoxide and hydroxyl radicals were found to be the main active species in the degradation process. This work recommended a novel Z-scheme heterojunction as a new idea for CFX removal. © 2020
Eskandari, P.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Jeon, B. Publication Date: 2019
Industrial and Engineering Chemistry Research (15205045)58(5)pp. 2099-2112
The synthesized TiO2/Fe2O3 nanostructures supported on powder-activated carbon (PAC) and zeolite at different mole ratios of Fe3+/TiO2 were characterized by XRD, XRF, FESEM, EDX, TEM, FTIR, BET, and, PL analyses and their cyanide photodegradation mechanism was thoroughly discussed. The results confirmed not only TiO2/Fe2O3/PAC had higher photocatalytic and adsorption capability but also better structural stability and reusability for cyanide removal than TiO2/Fe2O3/zeolite. The first-order kinetics model indicated that the photodegradation rate using TiO2/Fe2O3/PAC was 1.3 times higher than that of TiO2/Fe2O3/zeolite. The response surface methodology (RSM) assessment showed that pH, irradiation time and initial cyanide concentration using UV/H2O2/TiO2/Fe2O3/zeolite system had more effects on the degradation, respectively; whereas the effectiveness of UV/H2O2/TiO2/Fe2O3/PAC process was highly influenced by initial cyanide concentration than the other two parameters. High R2 and well-fitted residual plots approved the accuracy of the models in predicting the cyanide degradation efficiency using both the photocatalysts. © 2019 American Chemical Society.
Publication Date: 2019
International Journal of Environmental Science and Technology (17351472)16(11)pp. 7165-7174
Abstract: In this research, the interaction effects between pH (range from 2 to 5), temperature (20–60 °C), current density (5–20 mA/cm2), hydrogen peroxide per chemical oxygen demand H2O2COD (0.2–0.75), and reaction time (45–135 min) for spent caustic wastewater treatment were assessed through electro-photo-Fenton oxidation process by using response surface methodology. The optimum conditions for Esfahan oil refinery’s spent caustic wastewater treatment with an experimental COD removal of 97% were obtained at 4.5 (pH), 60 °C, 16.6 mA/cm2, 0.69 (H2O2COD), and 80 min. The interaction effects of hydrogen peroxide with pH; hydrogen peroxide with temperature; and temperature with reaction time were considered essential, which indicated the dependency among the factors. However, the interaction effect between pH and hydrogen peroxide was found so significant for chemical pollutant removal due to the activity of both iron ions and hydrogen peroxide. The pH reduction step of spent caustic (pH < 5) could lead toward the COD removal of 45% in the form of hydrogen sulfide gas. Complementary tests were run on the precipitated chemical sludge at optimal conditions to find organic contaminants, which indicated the chemical sludge mainly contains FeSO4 and Na2SO4. It was shown that advanced oxidation process for the degradation of contaminants was efficient and pollutants did not add to the sediment in the sludge phase. © 2019, Islamic Azad University (IAU).
Publication Date: 2019
Advances In Environmental Technology (24764779)5(1)pp. 55-65
A TiO2/Fe2O3/GO photocatalyst is synthesized via the sol-gel method and characterized by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), FT-IR, Brunauer-Emmett-Teller (BET), and Ultraviolet-Visible Diffuse Reflection Spectroscopy (UV-Vis DRS) analyses. Metronidazole (MET) concentration (10-20 mg/L), photocatalyst concentration (0.5-1.5 g/L), irradiation time (60-120 min), and initial pH (4-6) are investigated through response surface methodology (RSM), and the optimal process conditions are determined. The removal efficiency of MET with the TiO2/Fe2O3/GO photocatalyst is 97% under optimal conditions: a pollutant concentration of 10 mg/L, the irradiation time of 120 min, photocatalyst concentration of 1 g/L, and pH of 5. The influence of mineral salts concentrations (50-800 mg/L), including NaCl, Na2SO4, NaHCO3, KCl, MgSO4, and CaCl2, are examined at the initial pH of 5, photocatalyst concentration of 1 g/L, and pollutant concentration of 20 mg/L. According to the results, the reaction rate constant decreases with an increase in mineral salts concentrations up to 800 mg/L, especially with Na2SO4 (42.43% deactivation) and also with MgSO4 (38.08%) and NaHCO3 (37.73%), under the same operational conditions. The effects of mineral salts such as NaCl and KCl on the reaction rate constant for the contaminant removal efficiency have a downward trend until these salts reach a 200 mg/L concentration, and then they experience an upward trend. © 2019, Iranian Research Organization for Science and Technology. All rights reserved.
Behineh, E.S.,
Solaimany nazar a.r., A.R.,
Farhadian, M.,
Rabanimehr, F. Publication Date: 2019
Advances In Environmental Technology (24764779)5(4)pp. 229-237
A three-dimensional (3D) simulation of four photocatalytic microreactors is performed using mass and momentum balance equations. The simulated results are validated with the available experimental data for the photocatalytic removal of methylene blue (MB) in two microcapillaries as well as dimethylformamide (DMF) and salicylic acid (SA) in two microchannels. In the surface layers of the microreactor, a photo removal reaction takes place, and the kinetic rates are described by the Langmuir-Hinshelwood (L-H) model. The Damköhler number for these microreactors is less than one, which indicates that the mass transfer rate is limited by the reaction rate. The numerical study and kinetic constants determination are carried out by using computational fluid dynamic techniques. The 3D model predictions are in good agreement with the available experimental data sets. The results of the parametric study show that by increasing the microreactor length from 50 to 90mm, the removal efficiency improves from 76% to 93%. Moreover, the removal rate is increased by about 40% by reducing the microchannel depth from 500 to 100 µm. © 2019, Iranian Research Organization for Science and Technology. All rights reserved.
Publication Date: 2019
Journal of Environmental Management (10958630)243pp. 116-126
Two species of microalgae (Chlorella vulgaris and Dunaliella tertiolecta)as the biological agents along with ZnO nanoparticles as the photocatalyst were used to investigate the hydrocarbon removal efficiency from oily water samples. Firstly, the toxicities of the photocatalyst, normal paraffine hydrocarbons and their combination towards the microalgae were evaluated in terms of cell growth and chlorophyll content. The capability of algae to absorb the nanoparticles in the aqueous phase was confirmed by FT-IR spectroscopy. Then, the hydrocarbon removal efficiencies of the algae, photocatalyst and the combined photocatalyst-algae system were studied by measuring the residual hydrocarbon content of the samples. Results indicated that despite of the growth inhibitory effects of n-alkanes and nanoparticles on the examined algae, both of them could survive in the system. Dunaliella tertiolecta was more affected by normal paraffins while Chlorella vulgaris was more sensitive to ZnO nanoparticles. Both of the studied species were capable of hydrocarbon removal and the efficiency of Chlorella vulgaris was superior. The combination of algae and nanoparticles was also proved to have a synergistic effect on degradation of the hydrocarbon content of the medium. The obtained removal efficiencies for initial hydrocarbon concentrations of 0.05%, 0.1% and 0.5% (v/v)were 100%, 78% and 42% for Dunaliella tertiolecta-ZnO and 100%, 93% and 88% for Chlorella vulgaris- ZnO system, respectively. It can be concluded that the examined microalgae-nanoparticle system can be considered as a final polishing step in hydrocarbons removal from oily waters. © 2019 Elsevier Ltd
Publication Date: 2018
Scientia Iranica (23453605)25(3C)pp. 1395-1411
The sol-gel method was used for the synthesis of zero-valent iron/titanium dioxide supported on activated carbon (Fe0/TiO2/AC) adsorbents, and the adsorbents were comprehensively characterized by XRF, XRD, FT-IR, BET, FE-SEM, and EDX analyses. The batch experiments were performed to evaluate the effect of adsorbent type, pH of solution, pollutant initial concentration, and contact time on the 2,4-dichlorophenoxyacetic acid (2,4-D) adsorption efficiency. The equilibrium experiments revealed that the Langmuir isotherm was in good agreement with the adsorption equilibrium data, whereas the adsorption kinetic experiments indicated that the adsorption procedure was described perfectly through a pseudo-first-order kinetic model. The obtained maximum adsorption capacities from Langmuir isotherms of 86.5, 87.5, 86,57, and 88.76 mg/g were achieved for Activated Carbon (AC), zero-valent iron/activated carbon (Fe0/AC), titanium dioxide/activated carbon (TiO2/AC), and Fe0/TiO2/AC at the 2,4-D initial concentration of 90 mg/L, pH = 4 and 25°C, respectively. © 2018 Sharif University of Technology.All rights reserved.
Publication Date: 2018
Environmental Nanotechnology, Monitoring and Management (22151532)10pp. 212-222
The sol-gel procedure is applied to prepare zero-valent iron/dioxide titanium nanocomposite based on activated carbon and the nanocomposite is characterized by XRF, XRD, FT-IR, BET, FE-SEM and EDX analysis. The response surface methodology (RSM) of experimental design is adopted to evaluate the effects of five operational factors, including 2,4-D initial concentration, nanocomposite concentration, irradiation time, pH, and the ratio of hydrogen peroxide concentration to the 2,4-D initial concentration on the performance of photocatalytic degradation of 2,4-D. An increase in the 2,4-D initial concentration, nanocomposite concentration, and pH, reduces the 2,4-D degradation. The performance of degradation is increased and then slightly decreased by increasing the irradiation time and the ratio of hydrogen peroxide concentration to the 2,4-D initial concentration. The optimum conditions are determined at the maximum 2,4-D initial concentration, the minimum concentrations of nanocomposite and hydrogen peroxide, and neutral pH. © 2018
Publication Date: 2018
Environmental Nanotechnology, Monitoring and Management (22151532)10pp. 223-230
In this paper, the application of a thin-film composite Nanofiltration (NF) membrane with isoelectric point (IP) of 4.5 have been applied in textile wastewater treatment. Removal of acid blue 25, disperse red 73 and methylene blue dyes under operating conditions of initial concentration (40–180 mg/l), pH (3–10) and pressure (0.5–1.1 MPa) was investigated. Response surface methodology (Box-Behnken design) was employed to design runs and analyze the effects of operating parameters. According to the results, pH had the most significant impact on the removal efficiency of disperse red73 and acid blue 25 due to the electrical repulsive force and membrane swelling,while concentration had the most impact on methylene blue removal because of screening effect. NF removal performance showed removal enhancement to 91% and 92% at pH of 10 and concentration of 180 mg/l, for disperse red73 and acid blue 25, respectively while the maximum methylene blue removal efficiency of 86% was obtained at pH of 3 and 40 mg/l. The optimum pressure was observed at 0.8 MPa for disperse red and acid blue removal, while decreasing the pressure to 0.5 MPa showed better methylene blue removal. © 2018 Elsevier B.V.
Publication Date: 2017
Environmental Nanotechnology, Monitoring and Management (22151532)8pp. 92-96
Woolen textile industries produces a significant high contaminated wastewater streams which have raised environmental concerns as their turbidity (>40 NTU) and COD (>1500 mg/L) are very high. To address their issue, usually a high level of chemical treatment is utilized; however, the addition of such level of chemicals itself creates another issue such as high concentrated sludge. In this study, chemical pretreatment (FeSO4 as coagulant, 400–800 mg/L, pH 6–10,) experiments was employed to reduce COD and turbidity to maximum 200 mg/L and 25 NTU respectively. The chemically assisted nanofiltration (NF) process (operating conditions: 4–8 bar, COD of 50–200 mg/L and pH of 6–10) by using a commercial spiral wound polyamide nano filter (TFC) was used to treat a real woolen textile effluent. Response surface methodology (RSM) was employed to determine the effects of operating parameters. The results showed that the best conditions for the pretreatment process were pH of 8, FeSO4 of 600 mg/L. For the NF process, by increasing pH and pressure, removal efficiency of turbidity and COD increased up to 98%. However, by enhancing the color concentrations, the COD removal efficiency reduced to about 90%. The results demonstrated that NF process at optimum conditions and after chemical pretreatment has an effective efficiency for real textile wastewater treatment. © 2017 Elsevier B.V.
Publication Date: 2017
Iranian Journal Of Fisheries Sciences (15622916)16(1)pp. 188-199
This study aimed to investigate the concentrations of two heavy metals, lead and cadmium, in the water of Zayandehroud River which is surrounded by Zarinshahr rice farms. Water was sampled from a depth of 30 cm during June, July and August 2015, i.e. during the process of planting, growing and after harvesting, in three stations. Water was collected from three points; 20m before the farms, beside the farms and 100m after the farms. Three water samples and one trout fish (Salmo trutta) sample were collected each month and the concentrations of lead and cadmium were measured in the kidney, liver and gills of trout fish. The results showed that the amounts of lead and cadmiumin in the water were less and more than standard levels for these metals, respectively. The average concentrations of cadmium in the water were 15.81, 11.25, 8.92 μg/L during June, July and August, respectively. It is evident that the amount of cadmium in water was significantly higher in June during the planting phase and use of fertilizers and pesticides was more than the other months (p≤0.01). There was a correlation in cadmium and lead concentrations between water and fish organs (kidney, liver and gill).
Publication Date: 2017
Journal of Environmental Chemical Engineering (22133437)5(6)pp. 5707-5720
The photocatalysts of TiO2/Fe2O3 and ZnO/Fe2O3 based on clinoptilolite natural zeolite were synthesized by impregnation route and sol-gel methods The synthesized photocatalysts were characterized by XRD, XRF, EDX, FE-SEM, FT-IR, BET and UV–vis DRS analyses. The results of XRD, FT-IR, and EDX confirmed the presence of Fe2O3, TiO2, and ZnO nanoparticles on the surface of clinoptilolite. The FE-SEM results confirmed deposition of TiO2/Fe2O3 and ZnO/Fe2O3 on the surface of zeolite. The approximate particle size of TiO2/Fe2O3 and ZnO/Fe2O3 was 47 and 34 nm, respectively. According to the XRF results, the synthesized nanoparticles had Fe3+/TiO2 and Fe3+/ZnO molar ratios of 0.06 in TiO2/Fe2O3/Zeolite and ZnO/Fe2O3/Zeolite, respectively. Based on BET analysis, the surface area of TiO2/Fe2O3/Zeolite and ZnO/Fe2O3/Zeolite was about 112 and 289 m2/g, respectively. UV–vis DRS analysis confirmed that both TiO2/Fe2O3/Zeolite and ZnO/Fe2O3/Zeolite have high absorbtion capacity at visible light region. The performance of these two photocatalysts in degradation of diphenhydramine (DPH) from contaminated water was evaluated by investigating the effects of operational factors such as concentration of the contaminant (1–100 mg/l), photocatalysts (0.5–2 g/l), irradiation time (45–180 min), and pH (4–10). The results of the photocatalytic experiments revealed that the ZnO/Fe2O3/Zeolite had a more effective performance in degrading DPH, compared to TiO2/Fe2O3/Zeolite. Under the optimal conditions, the efficiency of DPH degradation with TiO2/Fe2O3/Zeolite (DPH: 50 mg/l, hydrogen peroxide: 50 mg/l, irradiation time: 120 min, photocatalyst: 0.5 g/l, pH = 5) and ZnO/Fe2O3/Zeolite (DPH: 50 mg/l, hydrogen peroxide: 50 mg/l, irradiation time: 100 min, photocatalyst: 0.5 g/l, pH = 10) was 80 and 95%, respectively. © 2017 Elsevier Ltd
Publication Date: 2017
Scientia Iranica (23453605)24(3)pp. 1221-1229
In this study, the performance of advanced oxidation process using titanium and iron oxides based on the natural clinoptilolite zeolite (TiO2/Fe2O3/Clinoptilolite) as a nanophotocatalyst was studied, and the effects of various factors on the furfural degradation, such as pH, dosage of catalyst, initial concentration of furfural, and contact time, were examined. The co-precipitation method was applied for the synthesis of the nanophotocatalyst. The SEM and XRD analyses showed a uniform distribution of titanium dioxide and iron nanoparticles on the zeolite. The furfural degradation could successfully happen at neutral to alkaline solutions. Moreover, increasing the amount of catalyst from 0.5 to 1.5 g/L does not have significant effects on the degradation efficiency. By enhancing the initial concentration of furfural from 75 to 300 mg/L, the rate of degradation decreases. The maximum efficiency of 98% could be achieved for 75 mg/L solution by using 1.5 g/L catalyst in pH equal to 8 within 120 minutes. © 2017 Sharif University of Technology. All rights reserved.
Publication Date: 2017
Journal of Chemical Technology and Biotechnology (02682575)92(9)pp. 2360-2368
BACKGROUND: Cyanide is a toxic compound used in gold mining, steel, electroplating and chemical industries. In this research, different mole ratios of Fe3+/ZnO supported on powder activated carbon (PAC) in the presence of H2O2 under UV irradiation were used to degrade cyanide contamination. The photocatalyst was characterized by XRD, XRF, FESEM, TEM and BET and response surface methodology was applied to assess the individual and interaction effects of several operating factors on cyanide degradation efficiency and to determine the optimization conditions. RESULTS: The results indicated that the average particle size of catalyst ranged from 20 to 60 nm. pH had the largest effect on response and there was interaction between initial cyanide concentration and pH. Decreasing the initial cyanide concentration and pH, while increasing the catalyst dosage, hydrogen peroxide concentration and irradiation time improved the cyanide degradation efficiency. The experimental result of cyanide degradation efficiency under optimum conditions ([CN]− = 250 mg L−1, photocatalyst = 1.4 g L−1, irradiation time = 180 min, pH=10, mole ratio of Fe3+/ZnO=6% and [H2O2] = 300 mg L−1) was about 98%. Photocatalytic activity was maintained even after seven successive cycles. CONCLUSION: The synthesized reusable high activity nanostructure photocatalyst can be considered an applicable and environmentally friendly catalyst for the decontamination of cyanide-polluted water. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry
Publication Date: 2017
Advances In Environmental Technology (24764779)3(4)pp. 205-216
The photocatalytic degradation of methylene blue was investigated with TiO2 and Fe2 O3 nanoparticles supported on natural zeolite. The synthesized photocatalyst was characterized by XRD, XRF, FT-IR, EDX, FE-SEM, and BET analyses. The results of XRD, FT-IR, and EDX confirmed the successful loading of Fe3+ doped TiO2 nanoparticles on natural zeolite. Further, the FE-SEM results confirmed the deposition of TiO2/Fe2 O3 on the zeolite, with the approximate particle size being 52.3 nm. According to the XRF results, the synthesized nanoparticles had Fe3+/TiO2 molar ratios of 0.06 in the synthesized photocatalyst. Based on BET analysis, the surface area of TiO2/Fe3+/natural zeolite was about 112.69 m2/g. The effects of operational factors such as pH (6-10), dye concentration (25-75 mg/L) and H2 O2 concentration (10-40 mg/L) were considered and optimized via response surface methodology utilizing Box-Behnken design. The optimization results indicated that the maximum percentage of degradation was achieved at a dye concentration of 25 mg/L, initial pH of 10, and H2 O2 concentration of 40 mg/L with a 90 min irradiation time and a 1 g/l photocatalyst concentration. The dye degradation efficiency reached 92% under this optimum condition. © 2017, Iranian Research Organization for Science and Technology. All rights reserved.
Esmaili, Z.,
Cheshmberah, F.,
Solaimany nazar a.r., A.R.,
Farhadian, M. Publication Date: 2017
Environmental Technology (United Kingdom) (1479487X)38(16)pp. 2040-2047
The aquaculture system is a potential significant source of antibacterial agents. The removal of florfenicol (Flo) antibiotic from synthetic aqueous wastewater is performed by applying a commercial thin film composite polyamide nanofilter (NF). For concentrated wastewater treatment, the advanced oxidation process (AOP) is applied. The effects of pH, pressure and Flo concentration on removal efficiency of NF and the effects of pH, Flo concentration and dosage of hydrogen peroxide and contact time on the AOP are assessed. In the nanofiltration system, it is found that an increase in pH enhances the removal efficiency up to 99%. In this membrane, an increase of pressure between 4 and 7 bar would increase the removal percentage, followed by a decrease from 7 to 10 bar. In AOP, it is observed that the degradation efficiency of Flo increases by both an increase in its initial concentration up to values above 50 ppm and contact time. The degradation efficiency of Flo is at its highest in the pH range of 7–10. With increasing H2O2 dosage, from 0 to 500 ppm, the removal efficiency increases. The results of this study indicate that a combination of a polyamide nanofilteration together with an AOP introduces an effective manner of removing Flo antibiotic from synthetic trout fish farm wastewater. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
Publication Date: 2016
International Journal of Environmental Science and Technology (17351472)13(3)pp. 763-772
Effluent sludge from an anaerobic digester was used as a source of nitrogen, phosphate, sulfur, and other nutrients in the culture medium of ethanol production by the yeast Saccharomyces cerevisiae. Several pretreatments (mechanical, chemical, thermal, and thermo-chemical) were performed on the anaerobic digested sludge (ADS) to make the nutrients accessible to the yeast cells. Preliminary experiments revealed that S. cerevisiae is not able to assimilate the carbon content of the ADS. However, when glucose was added to the medium, ethanol production was observed. The yield of ethanol using untreated ADS was only 10 % of the theoretical yield, but alkaline pretreatment improved it up to 43 %. By separating the hydrolysate of alkaline-treated ADS from the suspended solids, the ethanol yield from the supernatant was further improved up to 65 % of theoretical yield. Alkaline-treated ADS exhibited competitive performance with the mixture of yeast extract and mineral salts in ethanol fermentation. © 2015, Islamic Azad University (IAU).
Publication Date: 2016
Desalination and Water Treatment (19443994)57(16)pp. 7175-7181
Membrane technology is one of the most efficient approaches for the treatment of industrial wastewater and reuse. In this study, the influence of influential parameters, including pH, feed pressure, sulfate concentration, and chemical oxygen demand (COD) on the simultaneous removal efficiency of pollutants in Polyacryl Iran Company, were investigated by applying a commercial TFC polyamide nanofilter. The three leveled factors of sulfate and COD concentration, feed pressure, and pH were considered in the range of 550–1,283 mg L−1, 85–198 mg L−1, 0.5–0.9 MPa, and 5–9, respectively. By increasing pH from 5 to 9, the sulfate and COD removal efficiency increased up to 90%, and also by increasing feed pressure from 0.5 to 0.8 MPa, the removal rate of COD increased to 92%, whereas the effect of feed pressure on the sulfate removal was found insignificant. Results also indicated that an increase in the COD concentration resulted in a reduction in the removal efficiency of COD from 96 to 82%. On the other hand, by increasing the sulfate concentration to 800 mg L−1, an increase in the sulfate removal efficiency from 94 to 96% was observed. A further increase in the sulfate concentration resulted in the reduction of sulfate removal efficiency. © 2015 Balaban Desalination Publications. All rights reserved.
Publication Date: 2016
Research on Chemical Intermediates (09226168)42(5)pp. 4021-4040
In the current study, a nanophotocatalyst doped with of TiO2 and Fe2O3 nanoparticles supported on Iranian clinoptilolite was synthesized and characterized by XRD, XRF, SEM, and EDX analyses. The results suggested the successful loading of TiO2 and Fe2O3 nanoparticles onto the surface of clinoptilolite. The SEM images confirmed the average size of nanoparticles deposited on zeolite, which was about 20–40 nm. Furthermore, application of the synthesized photocatalyst in photocatalytic degradation of Acid Black 172 dye was studied using the Taguchi method and the chosen parameters were as follows: pH (2–7), dye concentration (50–200 mg/l), irradiation time (30–120 min), and catalyst dosage (0.5–1.5 g/l). The results indicate that dye concentration, pH, and irradiation time are respectively the most effective factors in these experiments while with the minimum dosage of the catalyst (0.5 g/l), up to 90 % removal efficiency could be achieved. The optimum value for each parameter was pH = 2, dye concentration = 50 mg/l, catalyst dosage = 1 g/l and irradiation time = 60 min, and the dye removal efficiency reached up to 100 % at these optimal conditions. Furthermore, after five-times recycling and reusing the catalyst, the efficiency of the photocatalytic degradation was reduced from 91.5 to 65.9 %, which is still an acceptable value. © 2015, Springer Science+Business Media Dordrecht.
Mahmoodi, P.,
Farhadian, M.,
Solaimany nazar a.r., A.R.,
Bashiri r., R. Publication Date: 2016
Advances In Environmental Technology (24764779)2(4)pp. 197-205
The interaction between the ions and the charge of membranes can affect the efficiency of pollutant removal. The present study investigated the removal efficiency of hexavalent chromium and nitrate ions from both actual and synthetic contaminated water via two different commercial spiral wound polyamide nanofilters. In addition, the interaction of ions under different experimental conditions was investigated by using a Box-Behnken design (BBD). The Box–Behnken design optimized the contributing factors which included pH (5-9), the initial concentration of Cr (VI) (0.05-5 mg/L) and the initial concentration of nitrate (40-160 mg/L). The maximum removal efficiency of both Cr (VI) and nitrate was achieved at a pH of 9.0, as 99 % and 90 % for the Iranian nanofilter (NF-I) and 98 % and 82 % for the Korean nanofilter (NF-K), respectively. The results also indicated that as the initial concentration of Cr (VI) increased, the removal efficiency was enhanced while the removal efficiency of nitrate decreased according to the pH. However, by increasing the initial concentration of nitrate, the removal efficiency of both the Cr (VI) and nitrate increased. For actual water samples at an optimum pressure of 0.6 Mpa (NF-K) and 0.8 Mpa (NF-I), the removal efficiency of Cr(VI) and nitrate obtained was 95% and 76 % for the NF-K and 97 % and 86 % for the NF-I, respectively. © 2016, Iranian Research Organization for Science and Technology. All rights reserved.
Publication Date: 2016
Desalination and Water Treatment (19443994)57(10)pp. 4439-4446
In this study, the performance of a novel configuration of the hybrid growth bioreactor in pilot-plant scale (containing of anoxic, aerobic and sedimentation sections) was investigated for Isfahan municipal wastewater treatment plants. The bioreactor performance was evaluated after primary sedimentation tanks under the inlet COD concentration of 0.27 ± 0.02 g/L, at different suspended biomass concentrations of about 3, 4, and 5 as g/L and different total hydraulic retention times 4, 8, and 12 h. An industrial moving bed packing with protected specific surface area of 350 m2/m3 was used in the bioreactor with a 30% of filling ratio. The modified Stover–Kincannon and Grau models are applied to predict the bio kinetic coefficients of COD removal. According to the results obtained, the substrate removal rate constant (ks) for Grau model was in the range of 8.23–10.96 (1/d), and the saturation constant (KB) value and the maximum total substrate utilization rate (Umax) for modified Stover–Kincannon were in the range of 57.4–87.7 (g/L d) and 62.6–91.4 (g/L d), respectively. Also, the results showed that the bioreactor follows the models with 98–99% correlation coefficients. © 2014 Balaban Desalination Publications. All rights reserved.
Publication Date: 2016
Desalination and Water Treatment (19443994)57(39)pp. 18194-18201
Abstract: Textile industries produce a large quantity of wastewater containing different dyes which can impose a significant risk to environment. In this study, the performance of a commercial polyamide nanofilter membrane for the removal of binary mixture of dyes of reactive (ionic) and disperse (non-ionic) dyes was investigated. The synergic effects of both dyes on the removal performance of the membranes were also studied. The experiments were performed at different dye concentrations of 60, 120, and 180 mg/l for each dye, pH of 6, 8, and 10, and for constant feed pressure of 800 kPa. Results showed that increasing pH from 6 to 10 and also disperse concentration from 60 to 180 mg/l enhanced the removal efficiency of both dyes about 10%. Whereas, by increasing the reactive dye concentration, disperse removal efficiency decreased by 3%. Response surface methodology was also used to optimize the effect of experimental parameters on the dye removal percentage. © 2015 Balaban Desalination Publications. All rights reserved.
Publication Date: 2016
Advances In Environmental Technology (24764779)2(2)pp. 95-103
An aquaculture system can be a potentially significant source of antibacterial compounds and ammonia in an aquatic environment. In this study, the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic aqueous wastewater was assessed by applying a commercial TFC (thin film composite) polyamide nanofilter. The effects of pH (6.5-8.5), pressure (4-10 bar), concentration of total ammonia nitrogen (1-9 mg/L), and florfenicol (0.2-5 mg/L) on the removal efficiency of the nanofilter were studied at a constant 70% recovery rate. It was found that by increasing the pH within the range of 6.5 to 8.5, it enhanced the removal efficiency by up to 98% and 100% for total ammonia nitrogen and florfenicol, respectively. With an increase in pressure from 4 to 7 bar, the removal percentage increased and then, it decreased from 7 to 10 bar. The interactions factors did not have significant effects on the both pollutants removal efficiencies. To obtain optimal removal efficiencies, an experimental design and statistical analysis via the response surface method were adopted. © 2016, Iranian Research Organization for Science and Technology. All rights reserved.
Publication Date: 2015
Advances In Environmental Technology (24764779)1(2)pp. 85-92
Decolorization of aqueous solutions containing ionic dyes (Reactive Blue 19 and Acid Black 172) by a TFC commercial polyamide nanofilter (NF) in a spiral wound configuration was studied. The effect of operating parameters including feed concentration (60-180 mg/l), pressure (0.5-1.1 MPa) and pH (6-10) on dye removal efficiency was evaluated. The response surface method (RSM) was utilized for the experimental design and statistical analysis to identify the impact of each factor. The results showed that an increase in the dye concentration and pH can significantly enhance the removal efficiency from 88% and 87% up to 95% and 93% for Reactive and Acid dye, respectively. Results showed that dye removal efficiency increased by an increase in pressure from 0.5 to 0.8 MPa, while further increase in pressure decreased the removal efficiency. The maximum dye removal efficiencies which were predicted at the optimum conditions by Design Expert software were 97 % and 94 % for Reactive Blue 19 and Acid Black 172, respectively. According to the results of this study, NF processes can be used at a significantly lower pressure and fouling issue for reuse applications as an alternative to the widely used RO process. © 2015, Iranian Research Organization for Science and Technology. All rights reserved.
Publication Date: 2015
Environmental Technology Reviews (21622523)4(1)pp. 71-89
Microbial fuel cell (MFC) is a novel technology that can be used for electricity generation during oxidization of the organic substances presented in the substrate. To obtain a desirable performance, it is essential to understand the influential factors on the MFC. Among the numerous factors affecting the MFC performance, substrate, microorganisms and their metabolism, electron transfer mechanism in an anodic chamber, electrodes material and the shape of electrodes, type of membrane, operating conditions such as temperature, pH and salinity, electron acceptor in a cathodic chamber and geometric design of the MFC are considered as the most important factors. Among different substrates, wastewater is a sustainable rich medium which can be treated by MFCs. There are various types of exoelectrogenic bacteria presented in wastewaters which can oxidize organic matter and transfer electrons to the anode without using mediators. Like other microbial systems, optimum pH and temperature enhance the bacterial growth which can improve the MFC performance. Despite the negative effect of salt on microbial growth, higher salinity and ionic strength can increase the conductivity of substrate and therefore enhance MFC performance. Scaling up MFC is a controversial issue which needs a comprehensive understanding of these factors. By using new inexpensive materials for electrodes and membrane for manufacturing MFCs, a more cost-effective design for scalable wastewater treatment and high power generation can be achieved. Furthermore, MFC is a suitable candidate for bioremediation of contaminated groundwater. These factors and their impact on the MFC performance have been reviewed in the present survey. © 2015, © 2015 Taylor & Francis.
Mahmoodi, P.,
Hosseinzadeh borazjani h., ,
Farhadian, M.,
Solaimany nazar a.r., A.R. Publication Date: 2015
Desalination and Water Treatment (19443994)53(11)pp. 2948-2953
Nitrate and diazinon pesticide is among the environmental challenges which enter water resources, mostly as a result of agricultural activities. In this study, the effects of diazinon concentration, nitrate concentration and pH on the efficiency of simultaneous removal of contaminants from polluted water were investigated, applying a commercial polyamide nanofilter. Each factor was considered in three levels where diazinon concentration, nitrate concentration and solution pH were in the range of 10–1,000 μg/L, 40–160 mg/L and 5–9, respectively. The experiments were conducted at constant pressure of 6 bar. The response surface method was adopted in the experimental design to obtain the impact of mentioned factors. It was found that increasing diazinon concentration and pH enhance the pesticide removal efficiency up to 94%, while increasing nitrate concentration increases the commercial nanofilter efficiency from 80 to 85%. The diazinon removal percentage at optimum condition was estimated to be about 93% at diazinon concentration of about 90 μg/L, nitrate concentration of about 80 mg/L and pH of 9. © 2014, © 2014 Balaban Desalination Publications. All rights reserved.
Publication Date: 2007
Bioresource Technology (09608524)98(16)pp. 3080-3083
The aim of this work was to study the treatment of strong beet sugar wastewater by an upflow anaerobic fixed bed (UAFB) at pilot plant scale. Three fixed bed bioreactors (each 60 L) were filled with standard industrial packing, inoculated with anaerobic culture (chicken manure, cow manure, anaerobic sludge digested from domestic wastewater) and operated at 32-34 °C with 20 h hydraulic retention time (HRT) and influent COD ranging between 2000-8000 mg/L. Under these conditions the maximum efficiency of organic content reduction in the reactor ranged from 75% to 93%. The reactor filled with standard pall rings made of polypropylene with an effective surface area of 206 m2/m3 performed best in comparison to the reactor filled with cut polyethylene pipe 134 m2/m3 and reactor filled with PVC packing (50 m2/m3). There was 2-7% decrease in efficiency with PE while it was 10-16% in case of PVC when compared to standard pall rings. The study provided a very good basis for comparing the effect of packing in reduction efficiency of the system. © 2007 Elsevier Ltd. All rights reserved.
