Mehmet KOBYA

Article | 2022 | Journal of Environmental Chemical Engineering10 ( 6 )

Heterogeneous electro-Fenton (EF) is a powerful technology for the removal of emerging organic pollutants from wastewater. However, the development of catalysts with high activity towards the production of •OH by decomposing H2O2 remains a challenge. Herein, Co-doped ZnFe LDH as a heterogeneous catalyst with 2D plate-like morphology was produced by a co-precipitation method. Co-doping increased the pore volume of ZnFe LDH from 0.188 cm3/g to 0.2711 cm3/g and pore diameter from 5.305 nm and 9.39 nm. EF process consisted of a hydrothermally activated graphite felt cathode and a platinum plate anode. The Phenazopyridine (PHP) removal e . . .fficiency of the EF process in the presence of Co-doped ZnFe LDH is twice that of the electrochemical process. Additionally, Co-doping increased the performance of ZnFe LDH from 60 to 82 due to a synergistic effect of redox couples of Fe2/Fe3 and Co2/Co3. The Co-doped ZnFe LDH/EF process achieved complete removal of PHP in real wastewater in 4 h and at natural pH. After 7 reuse cycles, the catalyst retained 91 of its performance. The eight by-products of PHP were determined by GC–MS. This work provides a way sustainable approach for the efficient removal of organic pharmaceuticals from wastewaters.Keyword: Emerging pollutants; Graphite felt; Hydrotalcite; Nanomaterials; Wastewater treatmen More less

Nahit AKTAŞ

Article | 2021 | Journal of Environmental Chemical Engineering9 ( 2 )

Among the various metal ions, chromate (Cr(VI)) and arsenate (As(V)) are the two most hazardous toxic ion species and are found in nature in the form of dichromate and arsenate anions. In this investigation, polyethyleneimine (PEI)-based hydrogels were prepared with microgel, cryogel, and bulkgel morphologies employing glycerol diglycidyl ether as a crosslinker. The prepared PEI-based hydrogels were used to remove dichromate and arsenate anions from aqueous media. PEI microgel, cryogel, and bulkgels weighing 50 mg of each adsorbed 84.7 /- 0.8, 76.5 /- 5.2, and 108.9 /- 2.4 mg.g(-1) of dichromate anions and 15.9 /- 0.7, 45.4 /- 1.9, . . .and 79.2 /- 11.6 mg.g(-1) of arsenate anions in 30, 120, and 240 min, respectively. The dichromate and arsenate anions adsorption of PEI-based hydrogels were found to fit to the pseudo-second-order kinetic, and nonlinear Langmuir isotherm models, respectively with higher R-2 values. The highest distribution coefficient (K-d) value of PEI-based hydrogels for dichromate adsorption was obtained on the cryogel forms of PEI as 1.89 /- 0.05. Likewise, the highest K-d value for the arsenate adsorption was calculated on PEI-based bulkgels as 0.46 /- 0.01. The thermodynamic parameters of PEI based hydrogels in the adsorption of dichromate and arsenate anions e.g., Delta G (all negative (except for the arsenate adsorption by PEI microgels), and Delta H that is around 2-10 kJ.mol(-1), and Delta S what is around 0.01-0.02 kJ.mol(-1). K-1 were calculated. The reusability studies showed that PEI-based hydrogels can be used for at least 5 consecutive adsorption-desorption cycles with almost 70 ?nion removal efficiency after the fifth cycle More less