Dual role of soil-derived dissolved organic matter in the sulfamethoxazole oxidation by manganese dioxide

Biwei Yang, Penghui Du, Guoping Chen, Peng Zhang, Qiang Zhang, Zhongying Wang, Gan Zhang, Zongwei Cai, Junjian Wang*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

6 Citations (Scopus)


Manganese dioxide (MnO2) can mediate organic pollutant oxidation in aquatic environments, which has been reported to be inhibited or promoted by dissolved organic matter (DOM) in different studies. It remains unresolved why conflicting results have been observed and whether such results depend on the type and concentration of DOM. Here, we used three types of well-characterized DOM derived from soil heated at 50, 250, or 400 °C (DOM_50, DOM_250, and DOM_400, respectively) to evaluate the impacts of DOM type and concentration and environmental pH on MnO2-mediated oxidation of sulfamethoxazole, a widely detected and ecotoxic emerging pollutant. We observed that the degradation rate of sulfamethoxazole was possibly promoted by DOM_250 (pH 6‒8), while it was generally inhibited by DOM_50 and DOM_400. Furthermore, it was initially inhibited and then promoted with increasing DOM concentrations and was consistently less inhibited at a higher pH. The inter-DOM variations of sulfamethoxazole degradation could be explained by the more enriched polyphenolics in DOM_250 than in DOM_50 and DOM_400, whereas the weak promoting effect of DOM_400 indicates that high DOM aromaticity may not necessarily promote pollutant degradation. Our results reconcile the debate on the role of DOM in the oxidation of sulfamethoxazole by MnO2 and highlight the decisiveness of the molecular composition and concentration of DOM and the reaction pH in the overall promoting or inhibiting role of DOM.

Original languageEnglish
Article number119901
Number of pages8
JournalWater Research
Early online date20 Mar 2023
Publication statusPublished - 15 May 2023

Scopus Subject Areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

User-Defined Keywords

  • Fourier transform ion cyclotron resonance mass spectrometry
  • Manganese dioxide
  • Oxidation
  • Soil-derived dissolved organic matter
  • Sulfamethoxazole


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