Dissolved organic matter promoted hydroxyl radical formation and phenanthrene attenuation during oxygenation of iron-pillared montmorillonites

Mengjing Guo; Longliang Wang; Haiyan Du; Fei Liu; Keli Yang; Yaoling Zhang; Shisuo Fan; Xin Liu; Huacheng Xu

doi:10.1016/j.chemosphere.2024.141264

Dissolved organic matter promoted hydroxyl radical formation and phenanthrene attenuation during oxygenation of iron-pillared montmorillonites

Chemosphere. 2024 Mar:352:141264. doi: 10.1016/j.chemosphere.2024.141264. Epub 2024 Jan 19.

Authors

Mengjing Guo¹, Longliang Wang², Haiyan Du², Fei Liu², Keli Yang³, Yaoling Zhang³, Shisuo Fan⁴, Xin Liu⁵, Huacheng Xu⁶

Affiliations

¹ State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, China.
² State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
³ Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China.
⁴ School of Resources and Environment, Anhui Agricultural University, Hefei, 230036, China.
⁵ Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China. Electronic address: liuxin@isl.ac.cn.
⁶ State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Technology Research and Development Center of Comprehensive Utilization of Salt Lakes Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China. Electronic address: hcxu@niglas.ac.cn.

PMID: 38244867
DOI: 10.1016/j.chemosphere.2024.141264

Abstract

The oxygenation of Fe(II)-bearing minerals for hydroxyl radicals (HO^•) formation and contaminant attenuation receives increasing attentions. However, information on dissolved organic matter (DOM) with different types, concentrations, and molecular weights (MWs) in manipulating HO^• formation and contaminant attenuation during mineral oxygenation remain unclear. In this study, four iron-pillared montmorillonites (IPMs) and two DOM samples [e.g., humic acids (HA) and fulvic acids (FA)] were prepared to explore the HO^• formation and phenanthrene attenuation during the oxygenation of IPMs in the presence or absence of DOMs. Results showed that iron-pillared and high-temperature calcination procedures extended the interlayer domain of IPMs, which provided favorable conditions for a high HO^• production from 1293 to 14537 μmol kg^-1. The surface-absorbed/low crystalline Fe(Ⅱ) was the predominant Fe(Ⅱ) fractionations for HO^• production, and presence of DOMs significantly enhanced the HO^• production and phenanthrene attenuation. Moreover, regardless of the types and concentrations, the low MW (LMW, <1 kDa) fraction within DOM pool contributed highest to HO^• production and phenanthrene attenuation, followed by the bulk and high MW (HMW-, 1 kDa∼0.45 μm) fractions, and FA exhibited more efficient effects in promoting HO^• production and phenanthrene attenuation than HA. The fluorescent spectral analysis further revealed that phenolic-like fluorophores in LMW-fraction were the main substances responsible for the enhanced HO^• production and phenanthrene attenuation. The results deepen our understandings toward the behaviors and fate of aquatic HO^• and contaminants, and also provide technical guidance for the remediation of contaminated environments.

Keywords: Dissolved organic matters; Hydroxyl radical; Iron-pillared montmorillonite; Molecular weight fractionation; Phenanthrene attenuation.

MeSH terms

Bentonite
Dissolved Organic Matter
Ferrous Compounds
Humic Substances / analysis
Hydroxyl Radical / chemistry
Iron* / chemistry
Phenanthrenes*

Substances

Iron
Dissolved Organic Matter
Hydroxyl Radical
Bentonite
Phenanthrenes
Ferrous Compounds
Humic Substances