Enhanced degradation of micropollutants using In situ electrogenerated sulfate radical at high flux.

ABSTRACT

The degradation of micropollutants via in situ-generated reactive species from coexisting substances in water is a promising approach for advanced water treatment. However, treatment efficiency and practical applications are hindered by limited operation conditions and prohibitive costs, respectively. Herein, we report an upgraded electrochemical filtration system that is chemical-free and made efficient by achieving in situ SO4•- generation at enhanced flux and in complicated water matrices. The ion transport was enhanced by coupled electric and flow fields, providing an outstanding performance in removing micropollutants. At the optimized conditions, the proposed system degraded 90.5% of bisphenol A (BPA) in 40 min and its degradation kinetics was 14.7 times that of the batch mode, and the treatment efficiency of the proposed system was 2.5 times more efficient than our previous design because of the enhanced flux. Quenching experiments indicate that indirect oxidation by SO4•- and •OH as well as direct electron transfer play critical roles during the BPA degradation. Importantly, the proposed system does not need any added chemicals and uses only the ubiquitous SO42- and electricity. From an environmental point of view, its energy conservation and the lack of additional chemicals ensure its applicability for purifying micropollutants.