MFC based in situ electrocatalytic persulfate activation for degradation of 2,4-dichlorophenol: Process and mechanism

Electrocatalytic persulfate (PS) generation of sulfate radicals has been extensively studied for the removal of organic pollutants, while continuous electricity output causes high energy consumption. Microbial fuel cell (MFC) is an environmentally friendly approach that can catalyze PS for degradation of pollutants through bioelectricity and achieve electricity recovery and utilization at the same time. In this study, a MFC based on electrocatalytic PS activation in cathode (PS-MFC) was constructed to remove 2,4-dichlorophenol (2,4-DCP) with simultaneous electricity recovery. Results showed that 2,4-DCP was successfully removed by PS-MFC with a maximum removal rate of 68.7% after 220 mins of reaction, and the removal process followed pseudo-second-order kinetic. In addition to the wide pH reaction range (pH 3–11), PS-MFC exhibited excellent electrical performance with a higher maximum power density (300.28 mW/m2) than reported studies of the similar type of MFC. Active species for the degradation of 2,4-DCP by PS-MFC system are O2•−, •OH, SO4•−and O21, with O2•− and •OH accounting for major part. The degradation pathway of 2,4-DCP in PS-MFC was proposed by free radical quenching experiments and intermediate product analysis. This work provided a green and sustainable solution for the removal of refractory organic pollutants and promoted research for the further practical application of MFCs.