摘要
Electrochemical degradation of sulfamethoxazole(SMX)and its metabolite acetyl-sulfamethoxazole(AcSMX)by Ti/SnO_(2)-Sb/Er-PbO_(2) were investigated.Results indicated that the electrochemical degradation of SMX and Ac-SMX followed pseudo-first-order kinetics.The rate constants of SMX and Ac-SMX were 0.268 and 0.072 min-1 at optimal curre nt density of 10 and 14 mA/cm^(2),respectively.Transformation products of SMX and Ac-SMX were identified and the possible degradation pathways,including the cleavage of S-N bond,opening ring of isoxazole and nitration of amino group,were proposed.Total organic carbon removal of SMX was nearly 63.2%after 3 h electrochemical degradation.22.4%nitrogen of SMX was trans formed to NO_(3)-,and 98.8%sulfur of SMX was released as SO_(4)2-.According to quantitative structureactivity relationship model,toxicities of SMX and Ac-SMX to aquatic organisms significantly decreased after electrochemical degradation.Electric energy consumption for 90%SMX and Ac-SMX degradation was determined to be 0.58-8.97 and 6.88-44.19 Wh/L at different experimental conditions,respectively.Compared with parent compound SMX,the metabolite Ac-SMX is more refractory and toxic,which emphasizes the importance of taking its metabolites into account when investigating the disposal of pharmaceuticals from wastewater.
基金
the National Science Fund for Distinguished Young Scholars(No.51625801)
the Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)
Guangdong Province Universities andColleges Pearl River Scholar Funded Scheme(2017)
the China Postdoctoral Science Foundation(No.2018M643671)。