Insights into the effects of natural pyrite-activated sodium percarbonate on tetracycline removal from groundwater: Mechanism, pathways, and column studies

Liu Guo; Ziqiu Nie; Lijia Wen; Bohan Chen; Jie Tang; Man Gao; Jiajing Chen; Jingjing Liu

doi:10.1016/j.scitotenv.2023.165883

Insights into the effects of natural pyrite-activated sodium percarbonate on tetracycline removal from groundwater: Mechanism, pathways, and column studies

Sci Total Environ. 2023 Dec 1:902:165883. doi: 10.1016/j.scitotenv.2023.165883. Epub 2023 Jul 28.

Authors

Liu Guo¹, Ziqiu Nie², Lijia Wen², Bohan Chen², Jie Tang³, Man Gao², Jiajing Chen², Jingjing Liu²

Affiliations

¹ State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & Water Pollution, Chengdu University of Technology, Chengdu 610059, China; College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China. Electronic address: [email protected].
² College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China.
³ State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil & Water Pollution, Chengdu University of Technology, Chengdu 610059, China; College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China.

PMID: 37517722
DOI: 10.1016/j.scitotenv.2023.165883

Abstract

In-situ chemical oxidation based on sodium percarbonate (SPC) has received much attention for remediation of groundwater contaminated with organic pollutants due to the high efficiency, stable reaction, and sustainability of SPC. Currently, metal ions and their composite materials, are mainly employed for the activation of SPC. However, due to its narrow pH range, slow Fe³⁺/Fe²⁺ circulation, and generation of refractory sludge, its application in groundwater is limited. In this study, SPC was activated with natural pyrite (FeS₂) to remove tetracycline, which was selected as the target pollutant. FeS₂ exhibited excellent catalytic activity and stability towards the degradation of tetracycline. The tetracycline degradation efficiency of SPC/FeS₂ system reached 70 % within 10 min, and nearly half of the tetracycline was degraded in the first 5 min of the reaction. The optimum SPC dosage for the tetracycline removal was 8 mM, with FeS₂ dosage of 0.5 g/L. The tetracycline removal efficiency remained above 60 % after 4 cycles, indicating its good recycling efficiency of the system. SPC/FeS₂ system was not significantly affected by the initial pH or the presence of Cl^-, SO₄^2-, NO₃^- while, HCO₃^-, Ca²⁺, Mg²⁺, and humid acid suppressed the reaction. The electron paramagnetic resonance spectroscopy and quenching experiments demonstrated that OH and O₂^- played a dominant role in tetracycline removal by the system. S₂^2-, as an electron donor, was able to participate in the Fe³⁺/Fe²⁺ cycle. In addition, the 13 transformation products were determined by liquid chromatography-mass spectrometry predicted that the degradation pathway of tetracycline consisted of hydroxylation, demethylation, and decarbonylation reactions. Finally, the dynamic simulation experiments of SPC/FeS₂ sand column showed that FeS₂ effectively activated SPC and significantly reduced the toxicity in groundwater after the packed column treatment. This study reveals that FeS₂ can efficiently activate SPC and has good prospects for tetracycline-contaminated groundwater remediation applications.

Keywords: Groundwater; Pyrite; Sodium percarbonate; Tetracycline.