Tags

Type your tag names separated by a space and hit enter

Electrochemical oxidation of sulfamethoxazole in BDD anode system: Degradation kinetics, mechanisms and toxicity evaluation.
Sci Total Environ. 2020 Oct 10; 738:139909.ST

Abstract

In the present study, electrochemical oxidation of sulfamethoxazole (SMX) with Boron-doped Diamond (BDD) anode and Stainless Steel (SS) cathode was investigated systematically. The effects of current density, initial pH, supporting electrolyte and natural organic matter (NOM) on SMX degradation were explored. Under the conditions of current density 30 mA cm-2, 0.1 M Na2SO4 used as supporting electrolyte, pH of 7 and without NOM affect, SMX was completely removed after 3 h electrolysis. COD removal efficiency, current efficiency and energy consumption were 65.6%, 40.1%, 72 kWh kg COD-1, respectively. Degradation mechanism was analyzed based on the active sites of SMX identified by density functional theory (DFT) calculation and intermediates analysis by HPLC-Q-TOF-MS/MS. Three possible degradation pathways were proposed, with the replacement of -NH2 at aromatic ring by -OH, the oxidation of -NH2 to -NO2 and the addition of -OH on isoxazole ring observed. The active sites detected in reaction matched the DFT calculation results exactly. The toxicity of intermediates produced during electrolysis process was evaluated by Escherichia coli experiment. Results showed that, after 2 h electrolysis, the inhibition ratio was decreased from the initial value of 22.8% to 10%, which has already achieved the safety boundary. After 4 h electrolysis, the toxicity was almost zero even with still 60% COD remained in the solution. This phenomenon demonstrated that the toxicity of SMX and its intermediate products was reduced significantly during electrolysis process.

Authors+Show Affiliations

Department of Environmental Science, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China.Department of Environmental Science, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China. Electronic address: xingxuanpku@163.com.Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.Department of Environmental Science, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China.Department of Environmental Science, College of Life and Environmental Science, Minzu University of China, Beijing 100081, China. Electronic address: Jxxia@vip.sina.com.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32531605

Citation

Hai, Hao, et al. "Electrochemical Oxidation of Sulfamethoxazole in BDD Anode System: Degradation Kinetics, Mechanisms and Toxicity Evaluation." The Science of the Total Environment, vol. 738, 2020, p. 139909.
Hai H, Xing X, Li S, et al. Electrochemical oxidation of sulfamethoxazole in BDD anode system: Degradation kinetics, mechanisms and toxicity evaluation. Sci Total Environ. 2020;738:139909.
Hai, H., Xing, X., Li, S., Xia, S., & Xia, J. (2020). Electrochemical oxidation of sulfamethoxazole in BDD anode system: Degradation kinetics, mechanisms and toxicity evaluation. The Science of the Total Environment, 738, 139909. https://doi.org/10.1016/j.scitotenv.2020.139909
Hai H, et al. Electrochemical Oxidation of Sulfamethoxazole in BDD Anode System: Degradation Kinetics, Mechanisms and Toxicity Evaluation. Sci Total Environ. 2020 Oct 10;738:139909. PubMed PMID: 32531605.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Electrochemical oxidation of sulfamethoxazole in BDD anode system: Degradation kinetics, mechanisms and toxicity evaluation. AU - Hai,Hao, AU - Xing,Xuan, AU - Li,Si, AU - Xia,Shuhua, AU - Xia,Jianxin, Y1 - 2020/06/03/ PY - 2020/02/25/received PY - 2020/05/31/revised PY - 2020/06/01/accepted PY - 2020/6/13/pubmed PY - 2020/8/19/medline PY - 2020/6/13/entrez KW - Boron-doped diamond anode KW - Degradation pathway KW - Electrochemical oxidation KW - Sulfamethoxazole KW - Toxicity analysis SP - 139909 EP - 139909 JF - The Science of the total environment JO - Sci. Total Environ. VL - 738 N2 - In the present study, electrochemical oxidation of sulfamethoxazole (SMX) with Boron-doped Diamond (BDD) anode and Stainless Steel (SS) cathode was investigated systematically. The effects of current density, initial pH, supporting electrolyte and natural organic matter (NOM) on SMX degradation were explored. Under the conditions of current density 30 mA cm-2, 0.1 M Na2SO4 used as supporting electrolyte, pH of 7 and without NOM affect, SMX was completely removed after 3 h electrolysis. COD removal efficiency, current efficiency and energy consumption were 65.6%, 40.1%, 72 kWh kg COD-1, respectively. Degradation mechanism was analyzed based on the active sites of SMX identified by density functional theory (DFT) calculation and intermediates analysis by HPLC-Q-TOF-MS/MS. Three possible degradation pathways were proposed, with the replacement of -NH2 at aromatic ring by -OH, the oxidation of -NH2 to -NO2 and the addition of -OH on isoxazole ring observed. The active sites detected in reaction matched the DFT calculation results exactly. The toxicity of intermediates produced during electrolysis process was evaluated by Escherichia coli experiment. Results showed that, after 2 h electrolysis, the inhibition ratio was decreased from the initial value of 22.8% to 10%, which has already achieved the safety boundary. After 4 h electrolysis, the toxicity was almost zero even with still 60% COD remained in the solution. This phenomenon demonstrated that the toxicity of SMX and its intermediate products was reduced significantly during electrolysis process. SN - 1879-1026 UR - https://www.unboundmedicine.com/medline/citation/32531605/Electrochemical_oxidation_of_sulfamethoxazole_in_BDD_anode_system:_Degradation_kinetics_mechanisms_and_toxicity_evaluation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(20)33429-X DB - PRIME DP - Unbound Medicine ER -