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论文类型：期刊论文

发表时间：2019-05-07

发表刊物：ENVIRONMENTAL SCIENCE & TECHNOLOGY

收录刊物：PubMed、SCIE、EI

卷号：53

期号：9

页面范围：5195-5201

ISSN号：0013-936X

关键字：Chemical activation; Cost effectiveness; Electrochemical electrodes; Electrochemical oxidation; Electrolytes; Inorganic compounds; Organic carbon; Sulfur compounds, Cost-effective methods; Electrochemical activation; Electrochemical degradation; Perchlorate electrolytes; Perfluorocarboxylic acid; Perfluorooctanoic acid; Persistent organic pollutants; Total organic carbon removal, Organic pollutants

摘要：Electrochemical oxidation based on SO4 center dot- and (OH)-O-center dot generated from sulfate electrolyte is a cost-effective method for degradation of persistent organic pollutants (POPs). However, sulfate activation remains a great challenge due to lack of active and robust electrodes. Herein, a B/N codoped diamond (BND) electrode is designed for electrochemical degradation of POPs via sulfate activation. It is efficient and stable for perfluorooctanoic acid (PFOA) oxidation with first-order kinetic constants of 2.4 h(-1) and total organic carbon removal efficiency of 77.4% (3 h) at relatively low current density of 4 mA cm(-2). The good activity of BND mainly originates from a B and N codoping effect. The PFOA oxidation rate at sulfate electrolyte is significantly enhanced (2.3-3.4 times) compared with those at nitrate and perchlorate electrolytes. At sulfate, PFOA oxidation rate decreases slightly in the presence of (OH)-O-center dot quencher while it declines significantly with SO4 center dot- and (OH)-O-center dot quenchers, indicate both SO4 center dot- and (OH)-O-center dot contribute to PFOA oxidation but SO4 center dot- contribution is more significant. On the basis of intermediates analysis, a proposed mechanism for PFOA degradation is that PFOA is oxidized to shorter chain perfluorocarboxylic acids gradually by SO4 center dot- and (OH)-O-center dot until it is mineralized.