Synergetic mechanism of defective g-C3N4 activated persulfate on removal of antibiotics and resistant bacteria: ROSs transformation, electron transfer and noncovalent interaction

Jin Wang; Mengmeng Dou; Xiaoyue Wang; Boru Gao; Tao Zhuang; Zhaokun Ma

doi:10.1016/j.chemosphere.2022.133741

Synergetic mechanism of defective g-C₃N₄ activated persulfate on removal of antibiotics and resistant bacteria: ROSs transformation, electron transfer and noncovalent interaction

Chemosphere. 2022 May:294:133741. doi: 10.1016/j.chemosphere.2022.133741. Epub 2022 Jan 28.

Authors

Jin Wang¹, Mengmeng Dou², Xiaoyue Wang², Boru Gao², Tao Zhuang³, Zhaokun Ma⁴

Affiliations

¹ Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing, Department of Municipal and Environmental Engineering, Beijing Jiaotong University, Haidian District, Beijing, 100044, China. Electronic address: jwang1@bjtu.edu.cn.
² Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing, Department of Municipal and Environmental Engineering, Beijing Jiaotong University, Haidian District, Beijing, 100044, China.
³ Jinan Environmental Research Academy, Jinan, 250102, China.
⁴ Shandong Academy for Environmental Planning, Jinan, 250101, China.

PMID: 35093423
DOI: 10.1016/j.chemosphere.2022.133741

Abstract

The environmental hazards of antibiotics and the resulting antibiotic-resistant bacteria (ARB) have attracted more and more attention. In this study, an efficient synergistic system constructed by vacancy g-C₃N₄ (CN_V0.8) and persulfate (PS) showed excellent oxidation performance to degrade aztreonam (AZT) and Escherichia coli (E. coli) screened from wastewater treatment plant (WWTP), as the typical β-lactam antibiotic and ARB. As the recombination of electron and hole was effectively inhibited and the interaction with PS was enhanced after the introduction of defects, CN_V0.8 showed superior PS activation ability compared with bulk-g-C₃N₄ (BCN). The synergistic mechanism was systematically analyzed at three levels step by step. Firstly, the conversion of reactive oxygen radicals (ROSs) was studied using electron spin resonance (ESR) and quenching experiments. Then based on the DFT simulation, the enhancement of adsorption energy between catalysts and PS from -8.924 eV (BCN) to -11.190 eV (CN_V0.8) and the elongation of O-O bond in PS (from 1.496 Å to 1.505 Å) indicated CN_V0.8 had better activation performance for PS compared with BCN. The electron transfer results observed by deformation charge density showed that more electrons could be transferred from the CN_V0.8 layer to the surrounding of PS for its own activation in the synergistic mechanism. Thirdly, the noncovalent interaction of PS/CN_V0.8 belonged to the region of van der Waals force which was defined by the reduced density gradient (RDG) analysis. The intermediate products in the degradation of AZT were first studied in detail using Fukui function calculations and HPLC-QTOF-MS analysis. Subsequently, the environmental practicability of the oxidation system was investigated through wastewater simulation. This research provides a possible strategy for the effective removal of micropollutants and promotes the development of the sulfate radical-advanced oxidation processes (SR-AOPs) in the field of wastewater treatment.

Keywords: Antibiotic; Antibiotic-resistant bacteria; DFT simulation; Vacancy g-C(3)N(4).

MeSH terms

Angiotensin Receptor Antagonists
Angiotensin-Converting Enzyme Inhibitors
Anti-Bacterial Agents / pharmacology
Electrons*
Escherichia coli
Oxidation-Reduction
Water Pollutants, Chemical* / analysis

Substances

Angiotensin Receptor Antagonists
Angiotensin-Converting Enzyme Inhibitors
Anti-Bacterial Agents
Water Pollutants, Chemical