Electrochemical activation of persulfate on BDD and DSA anodes: Electrolyte influence, kinetics and mechanisms in the degradation of bisphenol A

The combination of electrolysis and persulfate (PS) activation was investigated to enhance the degradation of bisphenol A (BPA) using boron-doped diamond (BDD) and dimensional stable anode (DSA) in perchlorate, sulfate, and chloride media. The acceleration effect of BPA degradation followed the order of Cl->ClO4->SO42- in BDD/PS and BDD system, while the degradation order in DSA/PS and DSA system was Cl->SO42->ClO4-. The contribution of radical species (SO4- and OH), active chlorine and electrolysis were confirmed for the degradation in different media with PS. Active chlorine dominated the degradation process with 85 % and 60 % removal in BDD/PS and DSA/PS system at 10 min, while the contribution of SO4- decreased from 20 % and 18 % in perchlorate to 5 % and 6 % in chloride media, respectively. The aromatic intermediates resulting from hydroxylation and carboxylation pathway and chlorinated products via hydroxylation and chlorine substitution pathway were detected in perchlorate and chloride media in BDD/PS system, respectively. The attempt of BDD/PS system in actual wastewater indicated potential for further application. This study aims to provide a deep insight to comprehensively understand the enhanced performance, contributions of different removal mechanisms, and degradation pathway of pollutants during the activation of PS in BDD and DSA systems in different media.