Organic ligands activate the dark formation of hydroxyl radicals (HO•) in surface soil/sediment: Yields, mechanisms, and applications

Yufan Yuan; Fangling Guan; Chenglong Yu; Danping Li; Faying Lai; Huajun Huang; Jinbao He; Yanpeng Gao; Hansun Fang

doi:10.1016/j.jhazmat.2022.130710

Organic ligands activate the dark formation of hydroxyl radicals (HO^•) in surface soil/sediment: Yields, mechanisms, and applications

J Hazard Mater. 2023 Mar 15:446:130710. doi: 10.1016/j.jhazmat.2022.130710. Epub 2022 Dec 30.

Authors

Yufan Yuan¹, Fangling Guan¹, Chenglong Yu¹, Danping Li¹, Faying Lai¹, Huajun Huang¹, Jinbao He¹, Yanpeng Gao², Hansun Fang³

Affiliations

¹ Key Laboratory of Poyang Lake Basin Agricultural Resource and Ecology of Jiangxi Province, College of Land Resource and Environment, Jiangxi Agricultural University, Nanchang 330045, China.
² Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Institute of Environmental Health and Pollution control, Guangdong University of Technology, Guangzhou 510006, China.
³ Key Laboratory of Poyang Lake Basin Agricultural Resource and Ecology of Jiangxi Province, College of Land Resource and Environment, Jiangxi Agricultural University, Nanchang 330045, China. Electronic address: fanghansun@163.com.

PMID: 36603429
DOI: 10.1016/j.jhazmat.2022.130710

Abstract

Soil is an important sink for various pollutants. Recent findings suggest that soil and sediment would spontaneously form HO^• through Fenton or Fenton-like reactions under natural conditions. In this study, the effects and mechanisms of organic ligands (OLs) on the occurrence of HO^• in surface soil/sediment were experimentally and computationally examined. Results confirmed that HO^• generation was ND-12.92 nmol/g in surface soil/sediment, and the addition of EDTA-2Na would significantly enhance the yields of HO^• by 1.4-352 times. Moisture was the decisive factor of soil HO^• generation. The release of Fe(II) from solid into the aqueous phase was essential for the stimulation of HO^• in EDTA-2Na suspensions. Furthermore, complexation reactions between Fe(II) and OLs would enhance single electron transfer (SET) reactions and the formation of O₂^•-. Interestingly, for specific OLs, their stimulations on SET and formation of O₂^•- would depress HO^• generation. Provoking HO^• generation by OLs could be efficiently used to degrade sulfamethoxazole in rice field sediment. The study provided new knowledge on how commonly synthetic OLs aﬀect the HO^• generation in surface soil/sediment, and it additionally shed light on the engineered stimulation of in-situ Fenton reactions in natural soil/sediment.

Keywords: Hydroxyl radical; Mechanisms; Organic ligand; Soil/sediment remediation; in-situ Fenton.