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Separation and Purification Technology (13835866)354
Janus membranes have asymmetric wettability on each side. This contrasting structure gives them an internal driving force for spontaneous fluid transport (caused by Laplace pressure). The objective of this research is to attain the maximum Laplace pressure for electrospun PVDF/PAN Janus membranes by adjusting the fiber diameter and, consequently, the pore size and contact angle in each layer of the membrane. To achieve this goal, the Taguchi method was employed, and the parameters of the electrospinning process were modified to determine the optimal conditions for obtaining the smallest and largest fiber diameters for PAN and PVDF polymers. Accordingly, four distinct types of Janus membranes with different morphologies in each layer were synthesized. SEM analysis was employed to characterize the structural and morphological properties of the fibers in each layer. Additionally, the contact angle (CA) was measured to assess the hydrophilicity of each layer and determine the droplet penetration rate across the membrane. According to the results, the maximum Laplace pressure (205.60 kPa calculated by the analysis of SEM images and 197.4 kPa calculated by the bubble point test) and highest droplet penetration rate (0.83 µL/s) were attributed to the Janus membrane with the lowest pore size in the hydrophilic layer (0.65 µm) and the highest pore size in the hydrophobic layer (3.44 µm). The performance of the optimized membrane was evaluated with respect to unidirectional water transport and water–oil mixture separation. The results showed a rectification ratio of 3.92, a permeate flux of 7.9 × 104 L·m−2·h−1·bar−1, and a separation efficiency of 96.8 %. Finally, it was demonstrated that the Laplace pressure of the optimal Janus membrane in this study is 2.66 times superior to that of the best similar one in previous studies. The appropriate and allowable range for pore size and contact angle, necessary to attain a satisfactory Laplace pressure (exceeding 100 kPa), has been explored, determined, and recommended for future researchers to foster inspiration in the field of Janus membranes. © 2024 Elsevier B.V.
Journal of Water Process Engineering (22147144)71
This research explores the separation of the antitumor drug doxorubicin (DOX) using smart membranes that respond to pH changes. To address the challenge of evaluating the efficiency of membranes with open and close gates, four types of membranes were synthesized: open gate (PADD0/PSf), bifunctional open gate (PADD1/PSf), close gate (PAADD0/PSf), and a combination of close/open gate (PAADD1/PSf). The results demonstrated that open gate membranes effectively separated DOX through molecular screening mechanism, with enhanced performance achieved through bi-functionalization and pH adjustments. The PADD0/PSf membrane exhibited a 93 % rejection rate at pH 7, which increased to approximately 99 % for the bifunctional PADD1/PSf at pH 2.7. In contrast, the PAADD0/PSf close gate membrane revealed only an 87 % rejection rate at pH 7, relying on Donnan repulsion for separation while achieving higher flux. Given the significance of treatment rates in membrane processes, the PADD0/PSf and PADD1/PSf membranes recorded fluxes of 4.6 LMH and 5 LMH at pH 7, respectively, while the PAADD0/PSf close gate membrane exhibited a significantly higher flux (226 %). The PAADD1/PSf close/open gate membrane was synthesized to optimize both separation and flux, achieving the highest flux at pH 2.7 with a 90 % DOX separation rate. At pH 11.2, it reached a separation rate of 95 % with a flux of 21 LMH, surpassing all other membranes across different pHs. Overall performance assessments indicated that PAADD1/PSf achieved an overall performance parameter of 1704 at pH = 2.7, compared to values of 78 for PADD0/PSf, 90 for PADD1/PSf, and 727 for PAADD1/PSf. © 2025 Elsevier Ltd
Chemical Engineering Science (00092509)316
Membrane fouling, a major challenge in filtration which lowers performance and membrane lifespan, is the focus of this research. The study introduces a key novelty by examining the combined effects of modifier type (mineral nanoparticles vs. organic substances) and their specific loading site (sublayer vs. top layer) on fouling mitigation, an aspect that has not been comprehensively addressed in prior studies. Hydrophilic mineral nanoparticles (CdSe, ZnSe, ZnTe) and dopamine hydrophilic organic substance were loaded in the sublayers of mixed matrix membranes (MMM) and the top layer of thin-film composite (TFC). Mineral modifiers outperformed organic counterparts. ZnSe nanoparticles was the most effective modifier; its strong hydrophilicity enhanced hydration layer formation, delayed phase inversion, and resulted in smaller pores and lower tortuosity in MMM (0,ZnSe), with the lowest pore fouling. Highlighting the significance of research, MMM membranes containing mineral modifiers (especially ZnSe) are suggested for lower pore fouling (4.62% vs 67.31%). In contrast, for lower cake fouling and higher rejection (98.00% vs 75.09%), TFC membranes containing both organic (dopamine) and mineral (especially ZnSe) modifiers are recommended. © 2025 Elsevier Ltd
This research principally aimed to present a suitable strategy for membrane-fouling mitigation in membrane-bioreactors (MBRs). The current strategies for membrane-fouling mitigation before initiating the process in many cases, are unmodifiable for a specific MBR system along the operations. Thus, membrane-fouling strategies during filtration should be applied. To select the best and most economical method for controlling fouling during the operations, the quality (site and mechanism) as well as quantity (thickness, mass, and porosity of the cake layer, and pore resistances) of fouling should be predicted. Accordingly, in this research, two powerful tools, i.e. modeling and simulation, have been used for predicting the quality and quantity of fouling, respectively. Through modeling, the best model describing the site and mechanism of fouling was chosen. Through simulation, the thickness, mass and porosity of the cake layer, along with resistance of cake and pores were calculated. In addition, the match between the results of modeling, simulation, and experimental results confirmed the accuracy of the performed predictions. Ultimately, to achieve the minimum membrane-fouling during filtration, based on the modeling results, the general solution of washing (physical or chemical), and based on the simulation results, its intensity (low, medium, and high) were proposed. © 2024 The Authors
The main objective of this article is to examine one of the most important challenges facing researchers in the field of nanocomposite membranes: what is the most suitable arrangement (unmodified, functionalized, coated, or composite) and the most suitable loading site for the nanostructure? In the review articles published on nanocomposite membranes in recent years, the focus has been either on a specific application area (such as nanofiltration or desalination), or on a specific type of polymeric materials (such as polyamide), or on a specific feature of the membrane (such as antibacterial, antimicrobial, or antifouling). However, none of them have targeted the aforementioned objectives on the efficacy of improving filtration performance (IFP). Through IFP calculation, the results will be repeatable and generalizable in this field. The novelty of the current research lies in examining and assessing the impact of the loading site and the type of nanostructure modification on enhancing IFP. Based on the performed review results, for the researchers who tend to use nanocomposite membranes for treatment of organic, textile, brine and pharmaceutical wastewaters as well as membrane bioreactors, the PESNHM, PANFe3O4/ZrO2M, PVDFCMC‐ZnOM, [Formula presented]M and PVDFOCMCS/Fe3O4M with IFP equal to 132.27, 15, 423.6, 16.025 and 5, were proposed, respectively. © 2024 The Authors
Chemical Engineering and Processing - Process Intensification (02552701)194
In the present research, with the aim of removing humic acid from wastewater, photo-catalytic membrane reactor was utilized. Single-component catalysts including ZnSe, CdSe, as well as composite catalyst (ZnSe/CdSe) were deposited in the surface layer of polysulfone membrane via photo-grafting method, whereby ZniCdjM membranes were synthesized. The results indicated that the ZnSe/CdSe due to its shorter bandgap, had a more effective role in the grafting process and hence adjusting the membrane pore size. The pore size of Zn4Cd4M was smaller than that of Zn4Cd0M and Zn°Cd4M, and hence the humic acid separation in the dark mode by Zn4Cd4M was 80 %, which is about 10 % greater than the value obtained by Zn4Cd0M and Zn°Cd4M. The ZnSe/CdSe due to its less photoluminescence emission, proved to be more effective in photocatalytic reactions compared to the single component catalysts. The extent of photocatalytic degradation of humic acid in the presence of UV-radiation by the Zn°Cd4M, Zn4Cd0M, and Zn4Cd4M was reported 80, 84, and 96 % respectively. Overall, due to the smaller pore size, shorter bandgap, and lower recombination, TOC removal by the Zn4Cd4M (containing composite catalyst) was reported 98 %, while this value for the Zn4Cd0M and Zn°Cd4M was reported 60 and 66 % respectively. © 2023 Elsevier B.V.
Journal of Environmental Chemical Engineering (22133437)11(5)
This research aims to separate doxorubicin (as a pH-sensitive antitumor-drug) by dual pH-responsive-membranes (pH-Res-Mems). Since the trade-off between flux and rejection is a limiting factor for pH-Res-Mems with pH alteration, the focus of this research is to apply a novel approach i.e., inducing pH sensitivity to both membrane surface and sub-layer, to resolve the mentioned problem. To this aim, metal-oxides with Close-Gate (CG) mechanism (changing pore-size based on OH- functional-group) including copper-oxide (Cu-pH-Res) and silicon-oxide (Si-pH-Res) or metal-organic-frameworks with Open-Gate (OG) mechanism (changing pore-size based on H+ functional-group) including ZIF-8 (Zn-pH-Res) and ZIF-67 (Co-pH-Res) were added to both membrane layers simultaneously, where SurCun/SubSim and SurZnn/SubCom membranes were synthesized. Addition of Zn-pH-Res and Cu-pH-Res to the surface-layer led to improved superficial properties including hydrophilicity and roughness, while adding Co-pH-Res and Si-pH-Res to the sub-layer resulted in improvement of structural properties such as porosity and pore tortuosity. Furthermore, investigation of the pH sensitivity of membranes indicated that for the SurCu3/SubSi3 membrane, with pH reduction, the overall performance (OP) was enhanced from 2.17 to 6.40, while for the SurZn3/SubCo3 membrane, with pH elevation, OP was enhanced from 2.19 to 16.8. Eventually, the investigations revealed that the SurZn3/SubCo0 single pH-Res-Mem at neutral pH offered rejection of 89%, permeability of 4.41 LMH, and fouling of 70.4%. Meanwhile, these values for the SurZn3/SubCo3 dual pH-Res-Mem at pH= 5.5 were 95%, 21.9 LMH, and 27.2%, respectively. Overall, SurCu3/SubSi3 and SurZn3/SubCo3 membranes succeeded in 91.9% and 94.5% DOX removal from actual hospital wastewater, respectively, indicating the high-efficiency of pH-Res-Mems. © 2023 Elsevier Ltd
Colloids and Surfaces A: Physicochemical and Engineering Aspects (18734359)678
In this research, pH sensitive bilayer membranes including ZIF-8 containing polyamide top-layer (ZnZIF) and ZIF-67 containing polyacrylonitrile sub-layer (CoZIF) named iZnZIF/jCoZIF were used for separating DOX1 pH-sensitive drug. Presence of CoZIF in the membrane sub-layer was associated with 26% increase in porosity and 9 nm RMS roughness reduction. It, in turn, caused elevation of flux from 3.7 to 9 LMH and flux recovery from 55% to 89% for the 0ZnZIF/1CoZIF membrane compared to the virgin membrane (0ZnZIF/0CoZIF). Presence of ZnZIF in the top-layer resulted in enhanced cross-linking (as confirmed by ATR2 test), boosted hydrophilicity, elevated surface charge density, increased surface layer thickness (as confirmed by SEM3 test), and reduced size of pores (as verified by MWCO4 test). Thus, the extent of flux recovery of DOX grew from about 55% for 0ZnZIF/0CoZIF to 90% for 1ZnZIF/0CoZIF membrane. Due to the synergistic effect of presence of pH-sensitive agents in both layers of the membrane, the flux, separation, and flux recovery of the 1ZnZIF/1CoZIF membrane reached 9.2 LMH, 92%, and 97%, respectively, showing 110%, 3%, and 7% enhancement compared to the 1ZnZIF/0CoZIF,2%, 10%, and 8% increase compared to the 0ZnZIF/1CoZIF membrane as well as 150%, 10%, and 42% growth compared to the 0ZnZIF/0CoZIF membrane. BET test measured the membrane pore size at pH= 3, 7, and 9 as 41, 32, and 35 nm, respectively. The sensitivity of the membrane pore size to pH, on the one hand, and sensitivity of surface charge of DOX to pH, on the other, were associated with enhanced separation by pH variations of the environment for the membrane. Specifically, the flux, rejection, and cake resistance for the 1ZnZIF/1CoZIF membrane at pH= 5 were 21.8 LMH, 99%, and 17.4%, respectively, while these values at pH= 7 were 9.27 LMH, 92%, and 43.24%, respectively. © 2023 Elsevier B.V.
Chemical Engineering Journal (13858947)450
The aim of this study is to achieve the best performance for the photocatalytic membrane reactor (PMR) in cephalexin removal. To this end, SrTiO3 photocatalyst with the bandgap of 2.85 eV and crystalline size 50 nm is embedded in the membrane structure using four methods, including blending with membrane matrix (BM), photograft polymerization (GP), interfacial polymerization (IP) and spin coating (SC). Investigation the PMR performance shows that, due to high porosity (68 %), the maximum drug flux (371 L/m2h) passes through the BMi membrane. Because of high flux, BMi membrane suffers from high fouling where presence of SrTiO3 can reduce it by at most 6 %. On the other hand, presence of SrTiO3 across the IPi surface, because of high surface area for performing photocatalytic degradation reactions, causes reduction of membrane fouling by 69 % compared to the raw membrane. The largest share of cephalexin membrane separation (80 %), due to the minimum MWCO (660 g/mol), is related to SCi membrane and the greatest share of the cephalexin photocatalytic degradation (59 %) as the shortest bandgap (3.19 eV) is associated with the GPi membrane. Overall, the highest rate of cephalexin removal (membrane separation plus photocatalytic degradation) is reported for SCi membranes, followed by IPi, GPi and BMi membranes, respectively. Hence, in order to achieve high flux, BMi; low fouling, IPi; high photocatalytic degradation, GPi and high separation, SCi membrane are suggested. Given the challenge ahead of any type of catalytic reactor, the proper method should be chosen for embedding the catalyst within the membrane structure. © 2022 Elsevier B.V.
Separation and Purification Technology (13835866)282
To separate the antitumor drug doxorubicin by polyacrylonitrile (PAN)- polyamide (PA) thin film composite (TFC) membrane, different factors were exploited including adjusting the size of pores, membrane superficial charge, and pH of the medium. For this purpose, copper oxide nanoparticles and silica hydrogel were added to the superficial PA layer and PAN sublayer, respectively, whereby SiiPAN-CujPA membranes were synthesized. Energy Dispersive X-Ray Spectroscopy (EDS) test confirmed the presence of Cu in the superficial layer and Si in the sublayer. The effect of Si on enhancing the sublayer porosity was proven by scanning electron microscopy (SEM) images, and the impact of Cu on increasing the crosslinking of the superficial layer was demonstrated by attenuated total reflection-fourier transform infrared (ATR-FTIR) test. The results indicated that adding silica hydrogel to the raw Si0PAN-Cu0PA membrane, through 22% increase in membrane porosity, caused elevation of flux from 12.3 to 27.9 LMH for Si3PAN-Cu0PA membrane. Meanwhile, the level of rejection and flux recovery of this membrane eventually reached 77 and 58% respectively. Addition of copper oxide nanoparticles to the Si3PAN-Cu0PA membrane, through reducing the size of membrane pores from 6.2 to 4.7 nm, caused the Si3PAN-Cu3PA membrane rejection to grow to 86% and flux recovery to 97%. Eventually, upon elevating the pH from 2 to 8, because of shrinkage of the membrane pores according to the Brunauer–Emmett–Teller (BET) analysis, increased superficial charge and zeta potential as well as reduction of the membrane pHPZC, the doxorubicin rejection was boosted to 99.4%. © 2021 Elsevier B.V.
Ceramics International (02728842)47(14)pp. 20210-20219
Cobalt ferrite magnetic nanoparticles were synthesized and developed by a modified Pechini method using iron nitrate, cobalt nitrate, ethylene glycol (EG), and sucrose with different volumes of lemon juice (10, 20, 30, 40, 50, 60, and 70 ml) as the source of chelating agent as well as nonmagnetic elements such as Ca and Mg ions. The XRD patterns confirmed that all samples synthesized by different contents of extracted lemon juice had a cubic crystal structure with single-phase spinel. Scanning electron microscopy revealed that cobalt ferrite nanoparticles had a semi-spherical morphology. Also, the vibrating sample magnetometer indicated that the saturation magnetization of CoFe2O4 nanoparticles prepared with different values of extracted lemon juice increased from 18.6 emu/g for 10 ml extracted lemon juice to 75.7 emu/g for 50 ml extracted lemon juice, after which the saturation magnetization diminished. Afterwards, the CoFe2O4 nanoparticles were coated with polyethylene glycol (PEG) and doxorubicin (DOX) drugs, whereby drug delivery was detected at different pH levels. The CoFe2O4-PEG-DOX nanocomposite could release doxorubicin by more than 42% at pH = 5.4 in 75 h. © 2021 Elsevier Ltd and Techna Group S.r.l.
Chemical Engineering Research and Design (17443563)176pp. 202-217
In this research, to reduce fouling of polyacrylonitrile (PAN) membrane, first, zinc-oxide (ZnO) nanoparticles as hydrophilic agent was utilized and PAN/ZnO membrane was synthesized, then, sodium-alginate (SA) as nanoparticle regulating agent was deposited on ZnO (ZnO@SA) and PAN/ZnO@SA membrane was synthesized. The performance of the synthesized membranes in reducing fouling of humic acid (HA), bovine serum albumin (BSA), and SA was examined. Results showed PAN/ZnO were 10.5% more porous, 27% less tortuous as well as greater negative charge density compared to PAN membranes. Also, the contact angle was reduced from 42° for PAN to 27° for PAN/ZnO membranes; meanwhile, the PAN/ZnO suffered disadvantages including larger pore size, higher molecular-weight-cut-off (MWCO), and fewer pores. The SA coating via ordered arrangement of nanoparticles caused PAN/ZnO@SA to have a contact angle of 24°, further, the number of its pores was about 35% greater compared to PAN membranes. These changes caused the fouling of BSA, HA, and SA by PAN/ZnO to be 2.5, 13.6, and 46.6% lower compared to PAN membranes. By contrast, because of superior structural features like more hydrophilicity, porosity, pore number; less tortuosity, lower MWCO, and fewer pore sizes; these figures were reported 5.8, 17.1, and 58.2% for PAN/ZnO@SA membranes. © 2021 Institution of Chemical Engineers
Polymers for Advanced Technologies (10427147)32(12)pp. 4765-4786
In this research, thin-film composite (TFC) membranes were used for separating metronidazole antibiotic from effluents. In order to enhance the metronidazole separation performance, thin-film nanocomposite (TFNC) membranes containing copper sulfide nanoparticles as well as modified thin-film nanocomposite (MFTNC) membranes containing copper sulfide nanoparticles coated with acrylic acid were employed. The spherical morphology of CuS nanoparticles along with the acrylic acid chains coated on their surface was confirmed through TEM, scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS) analysis. The crystalline size of nanoparticles was obtained as 29 nm according to XRD. The effect of nanoparticles on chemical functional groups and membrane elemental analysis was investigated by FTIR and CHNS analysis. The structural comparison of TFC, TFNC, and MTFC membranes indicated that the degree of grafting (DG) of the composite thin-film was 17.2, 27.2, and 46.1%, respectively. The structural modification caused the contact angle of TFC, TFNC, and MTFNC to diminish by 47, 34, and 21°, and their porosity to rise by 37, 67, and 53%, respectively. Improvement of porosity and surface hydrophilicity resulted in flux recovery of 87, 100, and 100% in metronidazole filtration by TFC, TFNC, and MTFNC membranes respectively. AFM analysis reported lower roughness of TFNC and MTFNC compared to TFC roughness, obtained in response to less fouling for TFNC and MTFNC over TFC. The size of pores of TFC, TFNC, and MTFNC membranes was measured as 26.5, 16.8, and 14.5 nm respectively, bringing about metronidazole separations of 86.3%, 87.5%, and 98.3%, respectively. © 2021 John Wiley & Sons Ltd.
Polymers for Advanced Technologies (10427147)32(3)pp. 1345-1362
In this research, to enhance the efficiency of polyacrylonitrile, iron oxide (Fe3O4) nanoparticles were added to membrane matrix and M(0,1) (PA/FePAN) membrane was fabricated. To boost the effectiveness, the iron oxide/zirconium oxide composite nanoparticles (Zr©Fe) were added to the superficial polyamide layer to synthesize M(1,0) (Zr©FePA/PAN) membrane. In order to investigate the supplement role of Fe3O4 and Zr©Fe nanoparticles, both nanoparticles were added to PAN substrate and PA superficial layer, respectively, to fabricate M(1,1) (Zr©FePA/FePAN) membrane. The performance of nanocomposite membranes was compared with that of M(0,0) (PA/PAN) raw membrane. The results indicated that the contact angle of M(0,0), M(0,1), M(1,0), and M(1,1) membranes was 38, 32, 28, and 21, respectively. Presence of nanoparticles enhanced the membrane porosity, such that the porosity of M(0,0), M(1,0), M(0,1), and M(1,1) membranes was 24%, 27%, 30%, and 33%, respectively. MWCO for M(0,0), M(0,1), M(1,0), and M(1,1) membranes was 610, 595, 380, and 330 Dalton, respectively. Presence of nanoparticles reduced fouling from 22% for M(0,0) membrane to zero for M(1,1) membrane. Presence of Fe3O4 nanoparticles and Zr©Fe composite nanoparticles concurrently in both membrane layers eventually caused M(1,1) to have around 23% greater flux and 68% higher efficiency for cephalexin rejection compared to M(0,0). © 2020 John Wiley & Sons Ltd
Journal of Photochemistry and Photobiology A: Chemistry (18732666)390
In this research, enhanced ultraviolet (UV) irradiation was used to offer antifouling properties to the surface of polysulfone (PSf) membranes. For this purpose, a thin layer of polyacrylic acid (PAA) was grafted to the membrane surface through UV irradiation in order to synthesize PAA/PSf membrane. Aiming to enhance the performance of UV irradiation, copper sulfide (CuS) and acrylic acid coated copper sulfide (AA©CuS) nanoparticles were embedded in the acrylic acid thin layer where CuS/PAA/PSf and AA©CuS/PAA/PSf membranes were fabricated. Presence of CuS and AA©CuS enhanced the wavelength of excitability of polysulfone from 254 to 322 and 354 nm, respectively. Thus, UV irradiation for 165 min on the surface of PSf membrane caused heightened degree of grafting from 16 % for PAA/PSf to 19 and 46 % for CuS/PAA/PSf and AA©CuS/PAA/PSf membranes, respectively. UV Irradiation for 240 min in the presence of nanoparticles also caused the CuS/PAA/PSf and AA©CuS/PAA/PSf membranes to be 28 and 42 % more hydrophilic and 26 and 37 % less rough respectively compared to PAA/PSf membrane. The mentioned factors eventually contributed to 40 %, 23 %, and 20 % irreversible fouling for PAA/PSf, CuS/PAA/PSf, and AA©CuS/PAA/PSf membranes, respectively. © 2019 Elsevier B.V.
Biofouling (10292454)36(6)pp. 660-678
This research aimed to mitigate fouling in membrane bioreactors (MBR) through concurrent usage of zinc oxide as an antibacterial agent (A) and sodium alginate as a hydrophilic agent (H) within a polyacrylonitrile membrane (PM) structure. The antibacterial polymeric membranes (APM) and antibacterial hydrophilic polymeric membranes (AHPM) synthesized showed a higher porosity, mechanical strength and bacterial inhibition zone, and a lower contact angle in comparison with PM membranes. EDS, SEM and AFM analyses were used to characterize the chemical, structural, and morphological properties of PM, APM, and AHPM. The flux of PM, APM, and AHPM in MBR was 37, 48, and 51 l m−2 h−1 and COD removal was 81, 93.5, and 96.7%, respectively. After MBR operation for 35 days in an urban wastewater treatment, only 50% of the flux of PM was recovered, while the antibacterial and hydrophilic agents yielded a flux recovery of 72.7 and 100% for APM and AHPM, respectively. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Environmental Technology (United Kingdom) (1479487X)41(20)pp. 2683-2704
The aim of this research is benefiting from the synergistic effect of the simultaneous presence of Fe3O4 and ZrO2 in the form of Fe3O4-coated ZrO2 (Fe3O4@ZrO2) nanoparticles within the structure of PAN membrane to reduce membrane fouling. The role of Fe3O4 nanoparticles in increasing the pore size and magnetic saturation as well as the role of ZrO2 in decreasing surface roughness and hydrophobicity can mitigate membrane fouling in magnetic-assisted membrane bioreactors. For this purpose, Fe3O4, ZrO2, and Fe3O4@ZrO2 nanoparticles were embedded into PAN membrane structure and magnetic (M nM), hydrophilic (H nM), and magnetic-hydrophilic (HM nM) membranes were synthesized. H 1M (1ZrO2/PAN) membrane with a contact angle of 31 degrees, M 1N (1Fe3O4/PAN) with a pore size of 90 nm, and H 3M (3ZrO2/PAN) membrane with an RMS roughness of 13.5 nm were the most hydrophilic, porous, and smoothest membranes, respectively. High sensitivity to magnetic field along with high porosity, high hydrophilicity and low surface roughness simultaneously exist within the structure of MHMs membranes, such that MH 1M (1Fe3O4@ZrO2/PAN) indicated 116% greater flux, 121% greater flux recovery, and 85% less total filtration resistance in comparison with the blank membrane in magnetic membrane bioreactor, at a magnetic field intensity of 120 mT and MLSS = 10,000 mg/l. As an overall conclusion, the output of this research was compared with other research in term of normalized flux. Results reveal that at MLSS = 10,000 mg/l, HRT = 8 h and TMP = 0.3 bar, MH 1M membrane has normalized flux equal to 1.56 g/m2 h bar which is an acceptable value compared to normalized flux reported by other researchers. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Polymer-Plastics Technology and Materials (2574089X)59(7)pp. 733-752
In this research, with the aim of engineering arrangement of nanoparticles within membrane pores, ZrO2 nanoparticles was modified by sulfate and carboxylate functional groups. Thereafter, the filtration performance of PSf/ZrO2, PSf/Zr-COOH, and PSf/Zr-SO4 nanocomposites in treating textile wastewater were compared. SEM, EDX and AFM analysis showed that the functional groups manipulate surface and structural properties of the membranes. Therefore, water flux of 13PSf/2.68Zr-SO4 and 13PSf/2.68Zr-COOH were 42% and 32% more than those of 13PSf/2.68ZrO2. Moreover, dye rejection of 13PSf/2.68Zr-SO4,13PSf/2.68Zr-COOH and 13PSf/2.68ZrO2 was about 99% and 97% and 95%, which is 14%, 12% and 10% higher than raw membrane. © 2019, © 2019 Taylor & Francis.
Journal of Water Process Engineering (22147144)38
In this research, with the aim of achieving a high flux and rejection of cephalexin antibiotic simultaneously, separate modifications were performed on the membrane top layer (selective layer) and substrate layer (support layer). Fe3O4 (Fe) and ZrO2 (Zr) nanoparticles were synthesized for modifying the PAN support layer, while Fe3O4/ZrO2 (FZ) nanoparticles were synthesized for modifying the PA top layer. In this regard, five types of nanocomposite membranes were synthesized: In order to regulate the porosity of the support layer, [Formula presented] and [Formula presented] membranes were synthesized which showed more pores number compared to [Formula presented] membrane. In order to enhance the surface hydrophilicity, [Formula presented] membrane was synthesized, which showed around 16% lower contact angle and 58% greater roughness compared to [Formula presented] membrane. In order to compensate for the roughness developed on the membrane surface, concurrent modifications were performed on the top and support layers; the [Formula presented] and [Formula presented] membranes were synthesized, which separated cephalexin by 91% and 95.8%. Comparison of the performance of the synthesized membrane with that of commercial FILMTEC (NF270-2450) membrane showed that the cephalexin rejection (95 ± 1) and flux recovery (99 ± 1) of [Formula presented] are almost the same as cephalexin rejection (98 ± 1) and flux recovery (96 ± 1) of commercial membrane. From permeation point of view, [Formula presented] membrane at transmembrane pressure of 4 bar and cross flow velocity of 0.5 m/s had a water flux of 49 L/m2.h and cephalexin flux of 38 L/m2.h, while NF270-2450 at the same condition had a water flux of 42 L/m2.h and cephalexin flux of 25 L/m2.h. © 2020 Elsevier Ltd
Environmental Chemistry Letters (16103653)18(1)
Zeolitic imidazolate frameworks (ZIF) have a flexible structure, controllable pore size, and thus adjustable properties, which make them effective materials for membrane separation. They have been used as a pure membrane in about 55% of cases, and as a structure modifier of mixed matrix membranes in other cases. ZIF-based membranes have been applied in pervaporation, nanofiltration, reverse osmosis and gas separation processes. This manuscript reviews the role of ZIF in promoting the membrane performance. A new performance parameter is defined based on permeability and selectivity, in order to compare the results of published reports. Findings show that the presence of ZIF in mixed matrix membranes improves the performances of pervaporation by 70%, nanofiltration by 211%, and reverse osmosis by 30%. ZIF also improved 11 times the membrane performance in gas separation, compared to the raw membrane. © 2019, Springer Nature Switzerland AG.
Journal of Porous Materials (15734854)25(4)pp. 1161-1181
The main purpose of this research is to use aluminum oxide nanoparticles in order to manipulate the formation mechanism of poly acrylonitrile (PAN) UF membranes with the aim of improving their performance in separating biological macromolecules including sodium alginate, humic acid, bovine serum albumin (BSA). For this purpose, alumina nanoparticles with the approximate size of 40 nm and high hydrophilicity properties were placed within the structure of the PAN membrane to engineering design of pores. Viscometry analysis and determination of cloud point were performed in order to investigate the formation mechanism of the nanocomposite membrane. Chemical, surface, and morphological variations of the nanocomposite membrane were evaluated using FTIR, zeta potential, contact angle, DLS, porosity metering, SEM, and AFM analyses. Eventually, investigation of the filtration performance of the nanocomposite membranes showed that the membranes containing 1 wt% of alumina nanoparticles have a water flux 57% more than that of raw membrane. Further, in terms of flux recovery parameter, this membrane indicated 22, 9, and 14% increase for sodium alginate, humic acid, and BSA, respectively. Regarding extent of dye separation, sodium alginate separation, humic acid separation, and BSA separation, 12, 7, 9, and 7% increase was observed for the nanocomposite membrane containing 3 wt% of alumina nanoparticles. © 2017, Springer Science+Business Media, LLC, part of Springer Nature.
Reactive and Functional Polymers (13815148)131pp. 299-314
This research proposes a novel method for intensifying the presence of nanoparticles on the top layer of blended nanocomposite membranes. To this end, carboxylic acid and sulfate functional groups were coated on the surface of zirconia nanoparticles. The functionalized nanoparticles were embedded in the matrix of PAN and PSf membranes, and six nanocomposite membrane models were synthesized including mZrO2@nPAN, mCZrO2@nPAN, mSZrO2@nPAN, mZrO2@nPSf, mCZrO2@nPSf, and mSZrO2@nPSf. The aim was to exploit proper arrangement of nanoparticles in the membrane matrix to strengthen the antifouling properties of the membrane. Overall, the change made in the superficial and structural properties of the membrane in response to presence of functional groups caused the internal pore blocking in 2.68CZrO2@13PAN and 2.68SZrO2@13PAN to be 50.9 and 41.8% less than that of the raw membrane, respectively. On the other hand, for the membrane lacking the functional group 2.68ZrO2@13PAN, this improvement was calculated to be only 30.9%. In terms of total fouling ratio, 2.68CZrO2@11PAN, 2.68CZrO2@13PAN, and 2.68CZrO2@15PAN membranes had 42.8, 39.3, and 35.6% less total filtration resistance respectively compared to the raw membrane. Considering PWF, 2.68SZrO2@13PAN and 2.68SZrO2@13PSf had 46.2% and 52.1% more PWF than bare 13PAN and bare 13PSf membrane. Regarding the role of functional groups in improving the membrane separation properties, mCZrO2@13PSf membranes improved dye separation percentage by 20%, compared to the raw membrane. On the other hand, 2.68SZrO2@11PSf membranes managed to separate 100% of Red BRLS dye due to the role of sulfate functional group in reducing the size of the membrane pores. © 2018 Elsevier B.V.
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
Chemical Engineering and Technology (09307516)40(1)pp. 76-87
A novel thin-film composite (TFC) nanofiltration membrane containing hydrophilic organic additives was fabricated via interfacial polymerization. Three organic acids, i.e., lactic, maleic, and citric acid, served as aqueous-phase additives and their role in membrane structure and nanofiltration membrane flux enhancement was investigated. Fourier transform-infrared (FT-IR) analysis confirmed the presence of organic acids in the polyamide (PA) layer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses were applied to investigate the membrane morphology. The more carboxylic functional groups present in the additive resulted in higher hydrophilicity and porosity and flux was enhanced significantly compared to the neat PA membrane, while salt rejection was influenced only to a minor extent. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Ceramics International (02728842)43(18)pp. 17174-17185
In this research, to benefit from the hydrophilic properties of zirconia nanoparticles as well as the role of iron oxide nanoparticles in improving porosity of polymer membranes simultaneously, Fe3O4@ZrO2/PAN nanocomposite membrane was synthesized and its performance was examined in reducing biological fouling of the membrane. FESEM analysis confirmed a size distribution of 35–55 nm, and TEM analysis confirmed a core-shell structure for Fe3O4@ZrO2 nanoparticles. FTIR analysis identified the functional groups in the Fe3O4@ZrO2 nanoparticles and confirmed their presence in the matrix of 1 Fe3O4@ZrO2/PAN NCM membrane. Contact angle analysis confirmed the role of zirconia nanoparticles in enhancing the membrane hydrophilicity by 51%, and porosimetry analysis confirmed the role of iron oxide nanoparticles in improving porosity of nanocomposite membranes by 47%. Usage of 1 wt% of Fe3O4@ZrO2 nanoparticles in the PAN membrane matrix brought about 40% increase in water flux and 37% growth in dye rejection for 1Fe3O4@ZrO2/PAN NCM membrane. Investigation of the role of Fe3O4@ZrO2 nanoparticles in the filtration of biological macromolecules indicated that 1 Fe3O4@ZrO2/PAN NCM membrane has 60%, 51%, and 56% less resistance to filtration of humic acid, sodium alginate, and BSA, respectively, when compared with raw membranes. © 2017 Elsevier Ltd and Techna Group S.r.l.
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.
RSC Advances (20462069)6(113)pp. 112269-112281
In this research, zinc oxide (ZnO) nanoparticles were used on a matrix of a polysulfone ultrafiltration membrane to make a nanocomposite membrane with a positive surface charge for filtration of biological macromolecules. The engineering of the biofilm structure developed onto the membrane surface leads to increased membrane flux, elevated rejection of protein, and reinforced antifouling properties of the membrane. AFM results indicated that the formed biofilm has increased roughness at higher pH levels. Further, FTIR analysis proved that the extent of biological macromolecules deposited on the membrane surface is greater at higher pHs. Through engineering the conditions of nanocomposite fabrication and adjustment of pH of the protein solution, the best antifouling performance was related to the nanocomposite containing 0.5 wt% of nanoparticles at pH of 8.9. Antibacterial tests proved the antibacterial properties of the nanocomposites containing ZnO nanoparticles. © The Royal Society of Chemistry.
Korean Journal of Chemical Engineering (19757220)33(11)pp. 3184-3193
The aim of this research was to synthesize a polysulfone/Zinc oxide nanocomposite membrane (PSf/ZnO NCM) in order to mitigate membrane fouling. ZnO nanoparticles with an approximate size of 20 nm were blended with PSf matrix. To fabricate an efficient PSf/ZnO NCM, polyethylene glycol and polyvinyl pyrrolidone were used as pore former agent, based on which PEG-NCMs and PVP-NCMs were fabricated. The effect of the type of pore former and concentration of nanoparticles was evaluated on the structure and performance of nanocomposite membrane. According to SEM images, with the increase in the concentration of nanoparticles, membrane porosity grew as well. AFM analysis confirmed increased roughness with contact angle measurement showing enhanced hydrophilicity. The filtration performance implied that the presence of ZnO nanoparticles improves water flux. Moreover, ZnO nanoparticles elevated humic acid rejection up to 99.7% and 94.2% and decreased total filtration resistance up to 89% and 30% for PEG-NCMs and PVP-NCMs, respectively. © 2016, Korean Institute of Chemical Engineers, Seoul, Korea.
Journal of Membrane Science (18733123)520pp. 881-894
The aim of this study is the synthesis of a magnetic nanocomposite membrane to reduce fouling in a magnetic membrane bioreactor. To this end, Fe3O4 nanoparticles with an approximate size of 60–70 nm were settled into the polysulfone ultrafiltration membrane matrix through blending of Fe3O4 nanoparticles with the dope solution. Nanocomposite membranes containing 0–0.11 wt% Fe3O4 nanoparticles submerged in the magnetic bioreactor system in which the MLSS was considered between 8000–16,000 g/L and the magnetic field intensity was 40–160 mT. The results showed that an increase in the concentration of nanoparticles reduced the filtration resistance as much as 48% and developed the COD removal as much as 24% and increased the flux as large as 30%. The presence of a magnetic field around the bioreactor reduced the total filtration resistance as much as 68% and increased the COD removal as much as 34% due to the production of some changes in the membrane morphology and the sludge properties. Comparing the performance of the synthesized nanocomposite membranes with a MICRODYN-NADIR commercial membrane sample showed that magnetic nanocomposite membranes possess 30% higher flux, 27% lower filtration resistance, 41% higher COD removal compared to a commercial membrane. © 2016 Elsevier B.V.
Desalination (00119164)377pp. 11-22
A novel sulfonated aromatic diamine monomer is used to provide thin-film composite (TFC) nanofiltration (NF) membranes with excellent performance and anti-fouling properties. A sulfonated TFC NF membrane was prepared through an interfacial polymerization reaction between amine agents in the aqueous phase and trimesoyl chloride (TMC) in the organic phase. Aqueous phase contained 2,5-diaminobenzene sulfonic acid (2,5-DABSA) as a sulfonated amine and piperazine (PIP) as a routine amine. The membrane performance results indicated that at 50% 2,5-DABSA, water flux reached 61.2L/m2·h demonstrating 34.2% higher water flux compared to membrane prepared by PIP without a significant change in salt rejection. The membrane was characterized using FT-IR, SEM, AFM, and contact angle methods. The results of contact angle and anti-fouling experiments proved that hydrophilicity of the membrane surface improved in the presence of 2,5-DABSA monomer. The high water flux was attributed to the presence of strong hydrophilic sulfonic groups at new polyamide layers leading to improved membrane anti-fouling properties. © 2015 Elsevier B.V..
Korean Journal of Chemical Engineering (19757220)33(8)pp. 2439-2452
The aim of this research is synthesis of high performance loose nanofiltration membranes for separation of direct dyes from textile wastewater. This involved sulfonation of polysulfone with the aim of increasing hydrophilicity and permeability; synthesis of a sulfonated polysulfone and polysulfone (SPSf/PSf) blended membrane for developing the mechanical resistance and stability of the filtration behavior; and synthesis of TiO2/SPSf/PSf nanocomposite membrane for magnifying selectivity. FTIR analysis confirmed the sulfonated groups and the TiO2 nanoparticles presence. AFM and SEM analysis proved the highest surface roughness and the smallest pore size of TiO2/SPSf/PSf nanocomposite membrane, respectively. The results of water absorption test revealed that the highest level of hydrophilicity belonged to the SPSf/PSf followed by TiO2/SPSf/PSf membrane. The nanofiltration tests showed that the SPSf/PSf membranes enjoy the highest permeability, while the TiO2/SPSf/PSf nanocomposite not only had an acceptable permeability but also presented the highest dye separation efficiency. © 2016, Korean Institute of Chemical Engineers, Seoul, Korea.
Journal of Industrial and Engineering Chemistry (1226086X)22pp. 357-367
In this study, polysulfone/alumina nanocomposite membranes were synthesized with the principal aim of reducing biofouling in membrane bioreactors. The filtration experiments indicate that alumina nanoparticles can increase water flux by enhancing membrane hydrophilicity while maintaining the separation efficiency through decreasing porosity. Altogether, as confirmed by AFM images, the development of roughness results in biofilm formation reduction on the membrane surface layer. On the whole, presence of alumina nanoparticles up to the polymer concentration of 0.03 wt.% will result in an augment in separation yield up to 7%, four times higher water flux, and 83% reduction in membrane fouling. © 2014 The Korean Society of Industrial and Engineering Chemistry.
Homayoonfalfini, M.,
Mehrnia, M.R.,
Shariaty-niassar, M.,
Akbari, A.,
Sarrafzadeh, M.H.,
Fauzi ismail, A. Desalination and Water Treatment (19443994)54(13)pp. 3603-3609
Abstract: In this work, separation of disperse dyes and polyethylene glycol (PEG) as organic contaminant by nanocomposite membrane was investigated. The main goal of this study is to achieve more efficient separation of contaminant from water at high fluxes. For this purpose, iron oxide nanoparticles (NP) were synthesized through co-precipitation, blended with polysulfone/N-methylpyrrolidone solution, and finally, dispersed in membrane structure after coagulation of casted polymeric solution. Effect of magnetic nanoparticle concentration on membrane structure and filtration performance was studied. According to filtration experiments, the increasing of nanoparticle concentration in membrane matrix cause permission flux to raise. On the other side, any increases in magnetic nanoparticle content improved disperse dyes and PEG rejection as organic contaminant. Iron oxide NP in polymeric solution act as an agent to increase viscosity and cause a delay in phase inversion, decrement in membrane pore size, and finally, solute rejection enhancement. The Fourier transform infrared spectroscopy confirmed nanoparticle existence in membrane matrix. Furthermore, the magnetic properties of nanocomposite membranes were measured by Vibrating Sample Magnetometer. Scanning electron microscopy images showed the effect of nanoparticle concentration on membrane porosity. The cross section of which confirmed the role of NP as a delay agent in membrane formation. © 2014 Balaban Desalination Publications. All rights reserved.
Desalination (00119164)372pp. 75-88
In this study the effects of Al2O3 nanoparticle concentration were investigated on the membrane structure/performance; the boundary of variations was detected, introduced as Nanoparticle Concentration Threshold (NCTh), and was used for forecasting the field of membrane application. For this purpose, Al2O3 nanoparticles with a size of 70. nm and a concentration between 0 and 0.52 Wt.% were added to the membrane matrix. Loading threshold of Al2O3 nanoparticles was evaluated and the properties of the nanocomposite membrane were compared up and sub the loading threshold. Rheometric analysis, contact angle measurement, SEM images, and filtration experiments showed that concentration threshold of Al2O3 nanoparticles was 0.39 Wt.%. Based on their properties, the antifouling performance of those membranes possessing Al2O3 concentration below the threshold was evaluated in a membrane bioreactor (MBR). © 2015 Elsevier B.V.
Homayoonfalfini, M.,
Mehrnia, M.R.,
Shariaty-niassar, M.,
Akbari, A.,
Fauzi ismail, A.,
Matsuura, T. Desalination (00119164)354pp. 125-142
The aim of this study is to investigate the effect of the presence and impregnation of iron oxide nanoparticles with the polysulfone membrane matrix. The nanoparticles were synthesized via co-precipitation method and were added to the membrane structure through blending with the polymeric matrix (Blended Nanocomposite Membranes (BNM)), deposition by photopolymerization (PhotoPolymerized Nanocomposite Membranes (PPNM)) and deposition by interfacial polymerization (Interfacially Polymerized Nanocomposite Membranes (IPNM)). FTIR analysis proved the presence of nanoparticles in all of the three types of membranes. According to AFM images, nanoparticles enhance the membrane roughness. On the account of SEM images obtained from the membrane surface, nanocomposite membranes have a more uniform surface compared to neat polymeric membranes. In addition, the cross-sectional SEM images of the membrane revealed that the blending method provides the opportunity of controlling the membrane morphology by means of nanoparticles. Contact angle analysis confirmed the development of nanocomposite membrane hydrophilicity versus neat polymeric membranes. The filtration experiments including permeation flux, dye rejection, and molecular weight cut off were done to compare all of the nanocomposite membranes. The results indicated that the blending method can improve the membrane structural properties and the deposition method can improve their separation yield. © 2014 Elsevier B.V.
Separation and Purification Technology (13835866)130pp. 74-83
In this study, pH-sensitive polysulfone (PSf)/polyacrylic acid (PAA) nanofiltration membranes were synthesized for separation of amoxicillin from pharmaceutical wastewater. Moreover, amoxicillin separation was enhanced by pH of filtration environment. In order to do so, a flat sheet ultrafiltration (UF) membrane with different pore sizes was prepared by the phase inversion process. A further layer of polyacrylic acid which is sensitive to filtration media pH was grafted onto this fabricated PSf UF membrane surface by UV-initiated graft. Efficiency of amoxicillin separation improved as a result of pH-sensitive nature of amoxicillin as well as surface activity and pH-sensitivity of developed nanofiltration membranes. The results confirmed that increase in molecular weight of polyethylene glycol (PEG) as the pore forming agent in the phase inversion stage, increased the pore size, the amount of acrylic acid deposition on the membrane walls and pH-sensitivity. Also, an increase in grafting intensity decreased the pore sizes and increased their surface charges as well as amoxicillin separation. AFM analysis showed that surface roughness decreases which reflect the reduction in deposition of acrylic acid onto membrane surface valleys. Since the membrane pores are electrically charged, which was confirmed by zeta potential measurement, when the pH of solution increases, the amoxicillin separation by these pH-sensitive membranes increases. Finally, the amoxicillin separation of synthesized nanofiltration membranes at pH = 10 successfully reached relatively high amount of 91%, while acceptable flux of 108.3 l h-1 m2 was maintained. The SEM images also confirmed increase in membrane pore sizes due to increase of PEG molecular weight. The FTIR analysis revealed that the amount of amoxicillin fouled on the membrane surface declined at higher pH due to high repulsion of amoxicillin by membrane. © 2014 Elsevier B.V. All rights reserved.
Journal Of Environmental Health Science And Engineering (2052336X)11(1)
In this study, high permeability flat sheet polysulfone nanofiltration membranes were prepared for amoxicillin (AMX) recovery from pharmaceutical wastewater. Membrane fabrication includes two steps: raw ultrafiltration membrane synthesis by phase inversion method and nanaofiltration membrane synthesis by surface photopolymerization. Raw ultrafiltration membranes were synthesized using different molecular weights of polyethylene glycol (PEG) as pore former and different coagulation bath temperatures (CBTs). The synthesized ultrafiltration membranes were modified using UV-assisted polymerization technique and their performance in the separation of AMX at different pHs, were studied. The results showed that the more irradiation time, the smaller surface pore size. Moreover, the membranes made with higher molecular weight of PEG and coagulation bath temperatures were more susceptible for UV-modification at these conditions; fabricated membranes had higher flux as well as relatively high AMX separation. Moreover, pH enhancement increased AMX rejection by 85%. The effect of irradiation on membrane surface morphology was studied by SEM surface images and the morphological effects of pore former and coagulation bath temperatures on membrane structure were confirmed by SEM cross section images. A fairly comprehensive discussion about the effects of PEG, coagulation bath temperature and irradiation time on membrane structure and AMX recovery performance was represented in this study. © 2013 Dirican et al.
Desalination and Water Treatment (19443994)51(16-18)pp. 3295-3316
Nanocomposite membranes benefit from both flexibility and processability of polymers and the thermal and mechanical stability of nanoparticles at the same time. This paper discusses the effect of the presence of various nanoparticles on the morphology and efficiency of the polymeric membranes in the separation of liquid phase. The presence of nanoparticles usually increases the hydrophilicity and decreases the fouling of polymeric membranes during the filtration process. The presence of TiO2, Al2O3, ZrO2, SiO2, Fe3O4, Ag, and Fe nanoparticles increases the mechanical and thermal resistant of the polymeric membranes. The TiO2 and Ag result in anti-bacterial characteristics, ZrO2 and Fe create catalytic properties, SiO2 nanoparticle causes conductivity properties, and Fe3O4 nanoparticle gives magnetic characteristics to polymeric membranes. Understanding the synthesis method (in situ or ex situ) and the combination routes (blending with polymeric matrix or deposition on the surface) of the used nanoparticles is very important in determining the structure and performance of the composite membranes during liquid filtration. Findings from such studies are highlighted and the future possibility of nanocomposite membrane application in liquid filtration is also discussed. © 2013 Copyright Balaban Desalination Publications.
Desalination and Water Treatment (19443994)51(34-36)pp. 6736-6742
Al2O3 nanoparticles were added to polysulfone (PSf) ultrafiltration membrane through the two methods of surface deposition and structure entrapment, to study the membrane performance in filtration of dye solutions. Alumina nanoparticles were synthesized through coprecipitation method and were added to casting solution containing PSf as a main polymer (17 wt.%), N-methyl-2-pyrrolidone as a solvent (75 wt.%), and polyethylene glycol with molecular weight of 400 as a pore former (8 wt.%). In addition, a deposition of nanoparticles onto the surface of the pre-prepared PSf membrane was formed by using photo-polymerization method. Water flux and rejection of disperse dye solution were studied afterwards. According to the obtained results, the synthesized nanocomposite membranes showed less flux decline but higher dye rejection in comparison with neat polymeric membranes. Results also showed higher dye rejection for membrane modified by entrapment method, while membrane modified by surface deposition method had higher dye flux. Fourier transform infrared spectrum analysis confirmed the presence of alumina nanoparticles in the structure and on the surface of the membrane. According to X-ray diffraction analysis results, the size of synthesized alumina nanoparticles were 16.61 nm and it reached 58.3 nm after being placed in the polymeric structure. © 2013 © 2013 Balaban Desalination Publications.
Water Science and Technology (02731223)64(12)pp. 2404-2409
A composite nanofiltration membrane was developed by a poly(acrylic acid) in situ ultraviolet (UV) graft polymerization process using an ultrafiltration polysulfone membrane as a porous support, by a phase inversion method. SEM images showed that the PSf membranes had numerous finger-like pores. Atomic force microscopy (AFM) showed that the roughness of the surface was reduced by an increase in UV irradiation times. The rejections of sodium chloride and sodium sulfate were moderate and declined with the increase of concentration. We observed that by increasing UV irradiation time and nanofiltration pressure applied, retention of dyes was enhanced and in the most irradiated membrane (M-4 membrane) at 4 bars, color removal with a high rejection of about 99.80% was achieved. It was found that the separation efficiency of dyes in the mixture of salt and dyes decreased with the salt concentration due to a decrease in the Donnan effect. It was also found that by varying the pH, the membrane surface and the dyes' charges are changed, which meant that the membrane surface and dyes had different interactions at various pHs. © IWA Publishing 2011.
Desalination (00119164)263(1-3)pp. 217-225
The rising demand for high quality water heightens the need to soften hard and very hard water. In this study, flat sheet polysulfone ultrafiltration membranes were prepared by phase inversion and modified by UV-induced polymerization of acrylic acid in order to prepare nanofiltration membranes for water desalination. Polyethylene glycol of different molecular weights mainly in the range of 1500-4000 Da were used in the casting solution and acrylic acid was polymerized on the membrane surface. In this way, a manipulated membrane was prepared with higher pore size and higher surface charge density for improved water softening. The results show that by increasing irradiation time and monomer concentration in the photografting process, pure water flux declines and salt rejection increases. For a membrane photografted for 180 min with acrylic acid solution (6 wt.%) and PEG-4000 as additive, the rejection of Na2SO4, MgSO4, NaCl and CaCl2 follows a decreasing in order of 100%, 77.9%, 49.9% and 35.9% respectively. The RMS roughness of the prepared membrane is 1.65 nm, which is well in the nanofiltration roughness range. Featuring a large pore size and high surface charge density, the developed nanofiltration membranes show a promising capability for water desalination. © 2010 Elsevier B.V.
Water Science and Technology (02731223)62(11)pp. 2655-2663
Composite nanofiltration (NF) membrane was developed polyacrylic acid (PAA) in situ UV graft polymerization process using ultrafiltration (UF) polysulfone (PSF) membrane as porous support. FT-IR spectra indicated that grafting was performed and it show peaks at 1,732cm-1 and 3,396cm-1 region for CO and OH starching bond of acrylic acid (AA) monomer, respectively. AFM microscopy showed the roughness of surface was reduced by increase of UV irradiation times. Effect of irradiation time on the grafting of acrylic acid (AA) in the same concentration was discussed. The salts rejection increase was accompanied with grafting of polysulfone (PSF) ultrafiltration (UF) membrane. The rejection of Na2SO4, MgSO4, NaCl and CaCl2 salts by PSF-grafted-PAA nanofiltration (NF) membrane was in 98, 60, 52 and 30% respectively, under 0.3 MPa. © IWA Publishing 2010.
Desalination and Water Treatment (19443994)9(1-3)pp. 43-48
The modified ultrafi ltration (UF) membranes were prepared by graft polymerization of acrylic acid (AA) that is a hydrophilic monomer onto the surface of ultrafi ltration membranes. Primary UF membranes were formed by wet phase inversion method by using polysulfone (PSf)/ N-methylene-2-pyrrolidone (NMP)/ poly (ethylene glycol) (PEG) casting solution and water coagulant. PEG acts as a pore-former that in this study is used in a wide range of molecular weights (M.W.) from 600 to 20000 Da. Changing the molecular weight of PEG additive, controls the structure and permeation properties of membranes. It can be observed that an increase in the molecular weight of PEG additive leads to an increase in water permeability. By increasing the irradiation time, rejection of dye and PEG increases, although solution permeability decreases. Increasing PEG rejection by increasing irradiation time shows the developing sieving mechanism by grafting and reduction in pore size. Grafting of AA onto membrane surface is confi rmed by InfraRed spectra (IR). Scanning electron microscopy (SEM) images show a signifi cant increase in membrane pore size than the one prepared from PEG 20000 Da, but its permeability is not too high to attribute to incomplete exit of this additive. Modifi ed membrane prepared from PEG600 (tirr = 30 min and [AA] = 6%) have desirable performance in separation of these dyes but other membranes prepared from higher M.W. PEG are not effective in separation of dyes. It was observed that this membrane showed acceptable performance both in terms of fl ux and rejection and has the characteristics of a NF-type membrane. © 2009, Taylor & Francis Group, LLC.
