Degradation kinetics and transformation pathway of methyl parathion by δ-MnO2/oxalic acid reaction system

Jianwei Wang; Weifeng Yue; Yanguo Teng; Yuanzheng Zhai; Hanhua Zhu

doi:10.1016/j.chemosphere.2023.138054

Degradation kinetics and transformation pathway of methyl parathion by δ-MnO₂/oxalic acid reaction system

Chemosphere. 2023 Apr:320:138054. doi: 10.1016/j.chemosphere.2023.138054. Epub 2023 Feb 3.

Authors

Jianwei Wang¹, Weifeng Yue², Yanguo Teng³, Yuanzheng Zhai⁴, Hanhua Zhu⁵

Affiliations

¹ College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China; Engineering Research Center of Groundwater Pollution Control and Remediation Ministry of Education, Ministry of Education of China, Beijing Normal University, China. Electronic address: wang2017bnu@163.com.
² College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation Ministry of Education, Ministry of Education of China, Beijing Normal University, China. Electronic address: yuewf@bnu.edu.cn.
³ College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation Ministry of Education, Ministry of Education of China, Beijing Normal University, China. Electronic address: teng1974@163.com.
⁴ College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation Ministry of Education, Ministry of Education of China, Beijing Normal University, China. Electronic address: diszyz@163.com.
⁵ Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China. Electronic address: hhzhu@isa.ac.cn.

PMID: 36739984
DOI: 10.1016/j.chemosphere.2023.138054

Abstract

Methyl parathion (MP) is a typical organophosphorus pesticide that is widely used worldwide, and hydrolysis, oxidation and reduction are the main abiotic degradation processes. Manganese dioxide (MnO₂) and organic acid can participate in various geochemical processes of pollutants, a reaction system was constructed to degrade MP using δ-MnO₂ and oxalic acid. The δ-MnO₂/oxalic acid reaction system could efficiently degrade MP, and the removal rate of MP (20 μM) reached 67.83% within 30 h under the optimized conditions (pH 5, [δ-MnO₂] = 2 mM, [oxalic acid] = 100 mM). MP was hydrolyzed by substitution reactions of S_N@P and S_N@C, and reduced by conversion of the nitro groups (-NO₂) in MP and its hydrolysates to amino groups (-NH₂). The primary active substance produced in the reaction system was the complexes dominated by Mn(III)-oxalic acid. This study provides a scientific basis for the degradation of organophosphorus pesticides using MnO₂ and an organic acid. The results have important theoretical significance and application value for pollution control and remediation of organophosphorus pesticides.

Keywords: Degradation mechanism; Methyl parathion; Transformation pathway; δ-MnO(2)/oxalic acid reaction system.

MeSH terms

Kinetics
Manganese Compounds / chemistry
Methyl Parathion* / chemistry
Organophosphorus Compounds
Oxalic Acid
Oxidation-Reduction
Oxides / chemistry
Pesticides* / analysis

Substances

Methyl Parathion
Oxides
Organophosphorus Compounds
Pesticides
Oxalic Acid
Manganese Compounds