Aqueous monomethylmercury degradation using nanoscale zero-valent iron through oxidative demethylation and reductive isolation

Ghulam Hussain Qasim, Hasan Fareed, Mijin Lee, Woojin Lee, Seunghee Han

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

This paper proposes a Fenton-like reaction activated by nanoscale zero-valent iron (nZVI) for aqueous monomethylmercury (MMHg) decomposition. Reacting 10 μg L−1 MMHg with 280 mg L−1 nZVI removed 70% of the aqueous MMHg within 1 min, and its main product was aqueous Hg(II). Within 1 − 5 min, the aqueous Hg(II) decreased while the aqueous, solid, and gas-phase Hg(0) increased with 92% MMHg removal. Then, a secondary Hg(II) reduction to solid Hg(0) was prevalent within 30 − 60 min, with 98% MMHg removal. Diverse-shaped magnetite crystals were observed on the surface of nZVI in 2 h, suggesting that Fe(II) oxidation on magnetite can be a source of electrons for secondary Hg(II) reduction. When FeCl2 and H2O2 were added to the MMHg solution without nZVI, 99% of the MMHg changed to Hg(II) within 1 min. The reactive oxygen species (ROS) produced by the Fenton-like reaction accounted for the rapid demethylation but not for the further reduction of Hg(II) to Hg(0). The results suggest a three-step pathway of MMHg decomposition by nZVI: (1) rapid MMHg demethylation by ROS; (2) rapid Hg(II) reduction by Fe(0); and (3) slow Hg(II) reduction by magnetite on the nZVI surface.

Original languageEnglish
Article number128990
JournalJournal of Hazardous Materials
Volume435
DOIs
Publication statusPublished - Aug 5 2022

Keywords

  • Demethylation
  • Monomethylmercury
  • Nanoscale zero-valent iron
  • Reactive oxygen species
  • Reduction

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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