Mechanistic insights into Cr(VI) removal by a combination of zero-valent iron and pyrite

Ruiming Zhang, Rossana Napolano, Beidou Xi, Anne Millicent Salazar, Qiantao Shi, Ying Zhao, Xiaoguang Meng

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Recent studies have revealed that a combination of zero-valent iron (ZVI) and pyrite (FeS2) can effectively remove (Cr(VI)) from water, but the reasons behind this synergistic effect are still unclear. Our batch experiments showed that dissolved oxygen (DO) is a critical factor in the improved removal of Cr(VI) by ZVI and pyrite. When 0.08 g/L pyrite was combined with 0.5 g/L ZVI in the presence of DO, total Cr was reduced from 10 mg/L to 0.02 mg/L within 6 h. Conversely, in the absence of DO, total Cr was only reduced to 5.6 mg/L. DO oxidation of pyrite produced protons that promote ZVI corrosion, and mixing pyrite with water creates dissolved sulfide, which also contributes to the improved removal of Cr(VI). Electron microscopy images and X-ray absorption near edge structure analyses revealed that the presence of dissolved sulfide led to the formation of ferrous sulfide precipitates on the ZVI surface, preventing the formation of a passivating layer.

Original languageEnglish
Article number138693
JournalChemosphere
Volume330
DOIs
StatePublished - Jul 2023

Keywords

  • Chromate
  • Dissolved oxygen
  • Pyrite
  • Reduction
  • Zero valent iron

Fingerprint

Dive into the research topics of 'Mechanistic insights into Cr(VI) removal by a combination of zero-valent iron and pyrite'. Together they form a unique fingerprint.

Cite this