Complexes of cupric ion and tartaric acid enhanced calcium peroxide Fenton-like reaction for metronidazole degradation
Shiyu Pan, Bo Cao, Deling Yuan, Tifeng Jiao, Qingrui Zhang, Shoufeng Tang
Abstract
To surmount the obstacles of traditional Fenton method and synchronously utilize Cu 2+ and polyphenol in water, an improved Fenton-like reaction applying calcium peroxide (CaO 2 ) as H 2 O 2 source and regulating by the complex of Cu 2+ -tartaric acid (TA, a representative of polyphenol) was constructed. A typical antibiotic , metronidazole (MTZ) could be effectively eliminated by the Cu 2+ /TA/CaO 2 system, and the optimized parameters were as follows: 0.1 mmol/L Cu 2+ , 2 mmol/L TA, 2 mmol/L CaO 2 , and initial pH 5. UV spectrum confirmed the formation of Cu 2+ -TA complex, which promoted the Cu 2+ /Cu + circulation through decreasing the Cu 2+ /Cu + couple redox potential , which further enhanced the H 2 O 2 decomposition and the formation of reactive species. Hydroxyl radical was dominant for MTZ degradation, followed by oxygen and superoxide radical. The degradation intermediates of MTZ were detected and their evolution way was speculated. Furthermore, the ternary process showed a wide pH tolerance (3–8) for removing MTZ and broad applicability for eliminating other dyes and antibiotics. This work provided a reference for Cu-based Fenton-like strategy for organic wastewater settlement.