Articles
Yavari, H.,
Bakht, Bahareh Khojasteh,
Zali boeini, H.,
Torabi, M.,
Shams Harandi M.,
Shams solari, I.,
Farahbakhsh, Z.,
Varma, R.S. Sensors and Actuators B: Chemical (09254005)379
A reversible multichannel chemosensor IPBTO [E)-5-(4-(1H-imidazo[4,5-b]phenazin-2-yl) benzylidene)-2-thioxothiazolidin-4-one] was fabricated as a D-pi-A system and used for the detection of cyanide ion (CN-) in aqueous solutions. This chemosensor exhibited a switch-off fluorescence response at 566 nm for CN- in the presence of other tested anions. The detection limit of IPBTO toward CN- was 0.7 mu M with the association constant being 2.0 x 106 M-1. The reversibility and reusability aspects of this chemosensor were investigated for five consecutive runs, and good results were obtained. In addition, IPBTO as a bioimaging agent with good cell viability was deployed for the detection of CN- in MDA-MB-231 cells. Excellent potential for sensing CN- was also realized for this chemosensor in food and environmental samples. Besides, IPBTO was self-assembled on the gold electrode surface (Au-IPBTO SAM) and used for accumulation and detection of CN- in aqueous media. This modified electrode was characterized by ATR surface analysis, and the electrochemical behavior of the electrode was studied utilizing cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Our results have conclusively revealed that this electrochemical sensor could be successfully used to detect CN-.
Separation and Purification Technology (13835866)
An extraction-electrooxidation (E-EODS) system is introduced for the removal of dibenzothiophene (DBT) from model fuel (DBT in n-hexane). The process is run in an electrochemical cell as a batch reactor, where, the model fuel is in contact with an appropriate immiscible polar solvent composed of acetonitrile and water (MeCN-water, 90:10% v/v) that serves as both the extraction solvent and electrochemical medium. The electrochemical oxidation of DBT, which is extracted into the MeCN-water phase, enhances the continuous removal of DBT from the model fuel phase. The effects of the composition of the extraction solvent, applied potential and the process time on DBT removal efficiency are assessed. The results indicate that with the selection of the MeCN-water, 90:10 v/v in a 1:1 ratio respect to the model fuel, this extraction method yields about 100% extraction efficiency within 5 h, at 25 °C at 2.9 V and atmospheric pressure as determined by HPLC technique. Cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) techniques are applied to identify the electrochemical oxidation products of DBT. The electrochemical oxidation-derived extraction process through this method is innovative and feasible for deep desulfurization of liquid fossil fuels. © 2021
International Journal of Hydrogen Energy (03603199)(1)
The glassy carbon electrode is modified by poly(brilliant cresyl blue) (PBCB) to be applied as a new green and efficient platform for Pt and Pt–Ru alloy nanoparticles deposition. Surface composition, morphology and catalytic activity of these modified electrodes towards methanol oxidation are assessed by applying X-ray diffraction, field emission scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy techniques. The X-ray diffraction patterns reveal that the highly crystalline Pt and Pt–Ru alloy and RuO2 nanoparticles with low crystallinity are deposited on the PBCB modified glassy carbon electrodes. The microscopic images indicate smaller size and better distribution of deposited nanoparticles on the surface of PBCB modified electrodes. Cyclic voltammetry and electrochemical impedance spectroscopy results reveal that PBCB supported Pt and Pt–Ru nanoparticles have better electrocatalytic performance and durability towards methanol oxidation rather than the unsupported nanoparticles. From the obtained results it can be concluded that the presence of PBCB not only improves the stability of nanoparticles on the surface, but also leads to the formation of smaller size and more uniform distribution of nanoparticles on the surface, which, in turn, cause the nanoparticles to provide a higher accessible surface area and more active centers for the oxidation of methanol. The results will be valuable in extending the applications of this polymer in surface modification steps and in developing promising catalyst supports to be applied in direct methanol fuel cells. © 2019 Hydrogen Energy Publications LLC
Chemical Engineering Journal (13858947)
Environmental-friendly waterborne polyurethane/graphene oxides nanocomposites (WPU/GOs) were prepared using p-tert-butyl calix[4]arene (BC4A) and sodium p-sulfonatocalix[4]arene (SC4A) modified GO nanosheets (CGO and SGO) as novel anti-corrosion coatings. Structural, thermal, and morphological investigation of nanosheets by FTIR, XRD, Raman, XPS, TGA, and SEM analysis confirmed their synthesis successfully. Moreover, different properties of WPU/GOs films were also evaluated by ATR-FTIR, XRD, SEM, contact angle, TGA, DSC and tensile analysis. It was found that the modification of GO nanosheets with BC4A and SC4A macrocycles not only overcome the flocculation and coagulation problem of unmodified GO incorporated WPU dispersion (WPU/GO) but also afford better mechanical properties to nanocomposites. The SEM morphological inspection exhibited that the microphase separation degree and dispersion quality of nanosheets within the nanocomposites strongly depends on the type of incorporated nanosheets. Regarding WPU/CGO and WPU/SGO nanocomposites, CGO and SGO nanosheets provide the enhanced storage stability and dispersibility compared to unmodified GO in WPU/GO sample. Anti-corrosion efficiency of the samples was also evaluated by PDS and EIS techniques and the results revealed that the WPU/CGO sample acts as a highly efficient anti-corrosion coating for mild steel and can be introduced as green corrosion protective coating with inhibition efficiency of 99.8%. © 2018 Elsevier B.V.
Colloids and Surfaces B: Biointerfaces (09277765)165pp. 135-143
Nickel-cysteine nanostructures (Ni-CysNSs) are prepared by a simple wet chemistry procedure under mild conditions, in which L-cysteine acts both as precursor and structure directing agent. This method involves the reaction of nickel chloride with L-cysteine, followed by simultaneous adjusting the pH in the range of 6–8.5 by addition of an aqueous NaOH solution. The structure and morphology of the prepared products are characterized using various techniques, including X-ray powder diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, CHNS elemental analysis, Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM). The effects of a variety of synthetic conditions on the structure and morphology of the Ni-CysNSs are studied, including the molar ratio of precursors, dispersing solvent, pH value of the reaction solution, reaction time and reaction temperature. FT-IR measurements reveal that synthesized Ni-CysNSs contain many free carboxylic groups on the surface, which could be used as binding sites to anchor biological molecules in order to develop various bioelectronic devices. In this work, the applicability of synthesized nanostructure in biosensing is studied by using Ni-CysNSs as a platform for covalently immobilization of GOx, as a model enzyme, on the surface. Cyclic voltammetric measurements reveal that the direct electron transfer from the active center of GOx to the glassy carbon electrode facilitated upon its immobilization on the Ni-CysNSs film. More importantly, GOx preserves its native structure and catalytic activity for the oxidation of glucose after immobilization on the Ni-CysNSs surface. The electrocatalytic characteristics of the GC/NiCysNS/GOx electrode toward the oxidation of glucose are investigated by cyclic voltammetry, which displayed acceptable electrical and sensing performance. Simple preparation of Ni-CysNPs and their biocompatibility make them attractive platforms for integration of various biomolecules such as proteine/enzymes with surface. © 2018
