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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Hydrogenation,Desulfurization,Thiophenic,MoS2 electrocatalyst,Membrane-electrode assembly
- چکیده:
- چکیده انگلیسی: The desulfurization-hydrogenation of thiophene and benzothiophene in hexadecane as a model diesel fuel was studied through a divided cell with the incorporation of a membrane electrode assembly (MEA) under different current density at a constant charge. The reduction of the thiophenic compounds was investigated using a prepared MoS2 nano-electrocatalyst, Nafion (commercial proton exchange membrane), and synthesized sulfonated poly ether ether ketone (SPEEK). Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) were used to characterize the MoS2 electrocatalyst, which confirmed the formation of 23-25 nm ball-like nano-threads of MoS2. Also, the electrocatalyst and/or MEA was electrochemically analyzed by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The gas chromatography-mass spectroscopy (GC-MS) analysis of the reactants and products revealed the direct desulfurization on the thiophene reduction process and the desulfurization along with the desulfurization pathway on the benzothiophene reduction experiment. A maximum desulfurization efficiency of 79.6% at 20 mA cm-2 and 51.5% at 30 mA cm-2 under the constant charge of 300 C was obtained for thiophene using the MoS2-Nafion and MoS2-SPEEK system, respectively. Moreover, a maximum hydrogenation and desulfurization efficiency of 28% and 59.1% occurred at 50 mA cm-2 and 70 mA cm-2, respectively, for the benzohiophene-Nafion system under the constant charge of 400 C. The distribution of the products affirmed that the desulfurization reaction contributed more at a higher current density against the hydrogenation process at a lower current density.
- انتشار مقاله: 15-03-1398
- نویسندگان: Foad Mehri,Soosan Rowshanzamir
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Cyclic Voltammetry,Wastewater treatment,Electrochemical oxidation,Anodic oxidation,Sulfide pollutant
- چکیده:
- چکیده انگلیسی: In this paper, cyclic voltammetry (CV) was used to study the effects of operating parameters (i.e., sulfide concentration, sodium chloride concentration as supporting electrolyte, temperature, mixing speed, and potential scan rate) on the anodic oxidation of synthetic sulfide-containing wastewaters at the surface of a platinum electrode. The results revealed that anodic oxidation could be used to eliminate sulfide from wastewaters in a wide concentration range, and the oxidation current was an ascending function of the sulfide concentration. The supporting electrolyte concentration had a negligible effect, as the sulfide dissociated in the aqueous media and brought electrical conductivity to the solution. The optimum concentration of electrolyte was found to be 0.05 mol/L. Increasing temperature improved the kinetics of the oxidation reactions and enhanced the electrical conductivity of the solution, which resulted in increasing the anodic oxidation rate. However, at higher temperatures, undesired side reactions were activated which resulted in lowering the power efficiency of the desired anodic oxidation reactions. The optimum operating temperature was found to be 40 – 60 °C. The mixing speed had a periodic effect on the sulfide oxidation. It decreased the diffusion resistance and also the residence time of sulfide at the electrode surface. These phenomena affected the anodic oxidation oppositely and hence, a middle value around 200 rpm was found to be the optimum. By increasing the potential scan rate, the time of performing the reactions in each cycle increased and the overall oxidation progress improved. It was found that mass transfer resistance was a limiting step in the overall reaction. Based on the findings, anodic oxidation has the potential for treating sulfide-containing wastewaters and in the future may be a competitor for conventional treatment processes.
- انتشار مقاله: 05-02-1397
- نویسندگان: Amir Behrouzifar,Soosan Rowshanzamir,Mansour Bazmi
- مشاهده