Decolorization of an azo dye Orange G in microbial fuel cells using Fe(II)-EDTA catalyzed persulfate

This study constructed a microbial fuel cell (MFC) using Fe(II)-EDTA catalyzed persulfate as the cathode solutions to decolorize Orange G (OG) and harvest electricity simultaneously. Chelated Fe2+ could activate persulfate to generate sulfate free radicals (SO4-) which with high oxidation potential (E0 = 2.6 V) can degrade azo dyes. The influence of some important factors such as pH value of cathode solutions, dosages of K2S2O8, Fe2+ and EDTA were investigated in a two-chamber microbial fuel cell. Under an optimal condition, the maximum power density achieved 91.1 mW m−2, the OG removal rate was 97.4% and the K2S2O8 remaining rate was 47.3% after 12 h. The OG degradation by Fe(II)-EDTA catalyzed persulfate was found to follow the second-order kinetic model.

► Microbial fuel cell using Fe(II)-EDTA catalyzed persulfate as the cathode solution. ► Microbial fuel cell degraded OG and harvest electricity simultaneously. ► The decolorization kinetics of OG followed the second-order kinetics well. ► EDTA could improve the stability of voltage output.