Nonradical oxidation from electrochemical activation of peroxydisulfate at Ti/Pt anode: Efficiency, mechanism and influencing factors.
Electrochemical activation of peroxydisulfate (PDS) at Ti/Pt anode was systematically investigated for the first time in this work. The synergistic effect produced from the combination of electrolysis and the addition of PDS demonstrates that PDS can be activated at Ti/Pt anode. The selective oxidation towards carbamazepine (CBZ), sulfamethoxazole (SMX), propranolol (PPL), benzoic acid (BA) rather than atrazine (ATZ) and nitrobenzene (NB) was observed in electrochemical activation of PDS process. Moreover, addition of excess methanol or tert-butanol had negligible impact on CBZ (model compound) degradation, demonstrating that neither sulfate radical (SO4-) nor hydroxyl radical (HO) was produced in electrochemical activation of PDS process. Direct oxidation (PDS oxidation alone and electrolysis) and nonradical oxidation were responsible for the degradation of contaminants. The results of linear sweep voltammetry (LSV) and chronoamperometry suggest that electric discharge may integrate PDS molecule with anode surface into a unique transition state structure, which is responsible for the nonradical oxidation in electrochemical activation of PDS process. Adjustment of the solution pH from 1.0 to 7.0 had negligible effect on CBZ degradation. Increase of either PDS concentration or current density facilitated the degradation of CBZ. The presence of chloride ion (Cl-) significantly enhanced CBZ degradation, while addition of bicarbonate (HCO3-), phosphate (PO43-) and humic acid (HA) all inhibited CBZ degradation with the order of HA >> HCO3-> PO43-. The degradation products of CBZ and chlorinated products were also identified. Electrochemical activation of PDS at Ti/Pt anode may serve as a novel technology for selective oxidation of organic contaminants in water and soil.
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Haoran
H
Song
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Linxia
L
Yan
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China. Electronic address: majun@hit.edu.cn.
Jun
J
Ma
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China. Electronic address: jiangjinhit@126.com.
Jin
J
Jiang
Shenzhen Water Affairs <Group> Co.Ltd., Shenzhen, Guangdong 518031, China.
Guangqiang
G
Cai
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Wenjuan
W
Zhang
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Zhongxiang
Z
Zhang
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Jiaming
J
Zhang
State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090, China.
Tao
T
Yang
D004566:Electrodes; D004572:Electrolysis; D010084:Oxidation-Reduction; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification
D014874:Water Pollutants, Chemical; D014025:Titanium
Electrochemical activation of peroxydisulfate; Nonradical oxidation; Selective oxidation; Ti/Pt anode