Magnetite drives self-dechlorination of 4-chlorophenol in anoxic aquatic sediments. (June 2021)

• Record Type: Journal Article
• Authors: Li, Yang; Ma, Ying; Zhao, Zisheng; Wen, Xin; Xu, Guangkuo; Jiang, Lin; Liu, Lifen; Zhang, Yaobin; Zhao, Zhiqiang
• Is Part Of: Chemosphere. Volume 273(2021)
• Publication Date: 2021-06
• Subjects: 4-Chlorophenol (4-CP) -- Dechlorination -- Anoxic aquatic sediments -- Magnetite -- Fe(III)-Reducing bacteria; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2021.129668
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The lack of available electron donors is well known as a major factor limiting the efficiency of microbial dechlorination of 4-chlorophenol (4-CP) in anoxic aquatic sediments. Considering that Fe(III) minerals largely contained in sediments can especially enrich Fe(III)-reducing bacteria and unlock the ring-like intermediates produced by dechlorination of 4-CP via dissimilatory Fe(III) reduction, a strategy of self-dechlorination of 4-CP utilizing its metabolism intermediates such as short-fatty acids (SCFAs) as the endogenous electron donors with magnetite was proposed in this study. The results showed that the removal efficiency of 4-CP increased by 156–203% in magnetite-supplemented biotic groups compared with the magnetite-free biotic group. Liquid chromatography-mass spectrometer (LC-MS) and gas chromatography (GC) revealed the possible metabolic pathway of anoxic 4-CP degradation with magnetite: 4-CP→phenol→cyclohexene-1-carboxylic acid→2-hydroxycyclohexanecarboxylic acid→hexanoic acid/valeric acid→butyric/propionic acids→CO2 . High-throughput sequencing analysis showed that the abundance of functional bacteria, Desulfuromonas, Pseudomonas and Bacillus species, were increased by 1.38–1.97, 1.50–2.04, and 11.60–17.18 folds in magnetite-supplemented biotic groups, compared with the magnetite-free biotic groups. Analysis of Fe 2+ concentration and cyclic voltammetry (CV) suggested that the potential Fe(III)/Fe(II) transformation occurred and proceeded the anoxic 4-CP degradation continuously. Graphical abstract: Image 1 Highlights: Self-dechlorination of 4-CP in anoxic aquatic sediments was achieved. Magnetite improved 4-CP removal efficiently with limited exogenous electron donor. Desulfuromonas, Pseudomonas and Bacillus were specially enriched by magnetite. Dissolved Fe(II) reacted with slight DO in anoxic sediments to form new Fe(III).