Effective peroxymonosulfate activation by natural molybdenite for enhanced atrazine degradation: Role of sulfur vacancy, degradation pathways and mechanism

Yanchun Huang; Leiduo Lai; Weifang Huang; Hongyu Zhou; Jun Li; Chao Liu; Bo Lai; Naiwen Li

doi:10.1016/j.jhazmat.2022.128899

Effective peroxymonosulfate activation by natural molybdenite for enhanced atrazine degradation: Role of sulfur vacancy, degradation pathways and mechanism

J Hazard Mater. 2022 Aug 5:435:128899. doi: 10.1016/j.jhazmat.2022.128899. Epub 2022 Apr 14.

Authors

Yanchun Huang¹, Leiduo Lai², Weifang Huang¹, Hongyu Zhou², Jun Li¹, Chao Liu¹, Bo Lai³, Naiwen Li⁴

Affiliations

¹ State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China; College of Water Resource & Hydropower, Sichuan University, Chengdu, Sichuan 610065, China.
² Department of Environmental Science and Engineering, School of Architecture and Environment, Sichuan University, Chengdu, 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China.
³ State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China; Department of Environmental Science and Engineering, School of Architecture and Environment, Sichuan University, Chengdu, 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China.
⁴ State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China; College of Water Resource & Hydropower, Sichuan University, Chengdu, Sichuan 610065, China. Electronic address: linaiwen@scu.edu.cn.

PMID: 35468392
DOI: 10.1016/j.jhazmat.2022.128899

Abstract

In this study, natural molybdenite (MoS₂) was applied to activate peroxymonosulfate (PMS) for the removal of atrazine (ATZ) and its degradation mechanism was investigated. Molybdenite exhibits superior catalytic performance. The best condition for atrazine degradation efficiency (>99%) was obtained with molybdenite concentration of 0.4 g/L, PMS concentration of 0.1 mM, and ATZ concentration of 12 μM within 10 min under experimental conditions. Electron paramagnetic resonance (EPR) test and chemical probe test further proved that HO^• and SO₄^•- played important roles in the molybdenite/PMS system, and SO₄^•- was dominant. Meanwhile, Electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) tests showed that sulfur vacancies and edge sulfur played important roles in the system. Edge sulfur was conducive to Mo⁴⁺ exposure, while sulfur vacancy facilitated electron transfer and reduced Mo⁶⁺ back to Mo⁴⁺. Combined with DFT calculation, the role of sulfur in the degradation process was verified. Besides, five ATZ degradation pathways were proposed. Finally, the degradation ability of the molybdenite/PMS system for different pollutants and in actual water bodies was also explored. This work provided ideas for exploring the degradation of organic contaminants by natural minerals.

Keywords: Atrazine; Degradation mechanism; Molybdenite; Peroxymonosulfate; Sulfur vacancy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Atrazine* / chemistry
Peroxides / chemistry
Sulfur
Water Pollutants, Chemical* / chemistry

Substances

Peroxides
Water Pollutants, Chemical
peroxymonosulfate
Sulfur
Atrazine