Manganese oxides mediated dissolve organic matter compositional changes in lake sediment and cadmium binding characteristics

Changsheng Jin, Zhongwu Li*, Andrew S. Hursthouse, Xiang Ding, Mi Zhou, Jia Chen, Bolin Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
9 Downloads (Pure)

Abstract

In sediment environments, manganese (Mn) minerals have high dissolved organic matter (DOM) affinities, and could regulate the changes of DOM constituents and reactivity by fractionation. However, the effects of DOM fractionation by Mn minerals on the contaminant behaviors remain unclear. Herein, the transformations of mineral phases, DOM properties, and Cd(II) binding characteristics to sediment DOM before and after adsorption by four Mn oxides (δ-MnO2, β-MnO2, γ-MnOOH, and Mn3O4) were investigated using multi-spectroscopic tools. Results showed a subtle structural variation of Mn oxides in response to DOM reduction, and no phase transformations were observed. Two-dimensional correlation spectroscopy based on synchronous fluorescence spectra and Fourier transform infrared spectroscopy indicated that tryptophan-like substances and the amide (II) N–H groups could preferentially interact with Cd(II) for the original DOM. Nevertheless, preferential bonding of Cd(II) to tyrosine-like substances and phenolic OH groups was exhibited after fractionations by Mn oxides. Furthermore, the binding stability and capacity of each DOM fraction to Cd(II) were decreased after fractionation based on the modified Stern-Volmer equation. These differences may be attributed to DOM molecules with high aromaticity, hydrophobicity, molecular weight, and amounts of O/N-containing group were preferentially removed by Mn oxides. Overall, the environmental hazard of Cd will be more severe after DOM fractionation on Mn minerals. This study facilitates a better understanding of the Cd geochemical cycle in lake sediments under the DOM–mineral interactions, and recommends being careful with outbreaks of aquatic Cd pollution when sediments are rich in dissolved protein-like components and Mn minerals.
Original languageEnglish
Article number114916
Number of pages10
JournalEcotoxicology and Environmental Safety
Volume256
Early online date14 Apr 2023
DOIs
Publication statusPublished - 31 May 2023

Keywords

  • cadmium
  • sediment
  • fractionation
  • dissolved organic matter
  • manganese oxide

Fingerprint

Dive into the research topics of 'Manganese oxides mediated dissolve organic matter compositional changes in lake sediment and cadmium binding characteristics'. Together they form a unique fingerprint.

Cite this