Reactive iron sulfide (FeS)-supported ultrafiltration for removal of mercury (Hg(II)) from water

Dong Suk Han, Maria Orillano, Ahmed Khodary, Yuhang Duan, Bill Batchelor, Ahmed Abdel-Wahab

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

This study investigated removal of Hg(II) from water using FeS(s) with batch and continuous contact filtration systems. For the batch system, kinetic experiments showed that removal of Hg(II) by FeS(s) was rapid at lower concentration (500μM), but at higher concentration (1000 and 1250μM), more time was required to achieve greater than 99% removal. The concentration of iron released to the solution remained relatively low, typically below 3μM. This would theoretically present less than 1% of the Hg(II) removed. Thus, a simple exchange of Hg(II) for Fe(II) in the solid (FeS(s)) does not explain the results, but if the Fe(II) released could react to form another solids, low concentrations of Fe do not preclude a mechanism in which Hg(II) reacts to form HgS and release Fe(II). A continuous contact dead-end ultrafiltration (DE/UF) system was developed to treat water containing Hg(II) by applying a FeS(s) suspension with stirred or non-stirred modes. A major reason for applying stirring to the system was to investigate the role of "shear" flow in rejection of Hg(II)-contacted FeS(s) by a UF membrane and the stability of Hg on the FeS(s). The Hg(II)-contacted FeS(s) was completely rejected by the DE/UF system and mercury was strongly retained on the FeS(s) particles. Almost no release of Hg(II) (≈0mM) from the FeS(s) solids was observed when they were contacted with 0.1M-thiosulfate, regardless of whether the system was operated in stirred or non-stirred mode. However, rapid oxidation of FeS(s) was observed in the stirred system but not in the non-stirred system. Determining the mechanism of oxidation requires further study, but it is important because oxidation reduces the ability of the solids to remove additional Hg(II).

Original languageEnglish
Pages (from-to)310-321
Number of pages12
JournalWater Research
Volume53
DOIs
Publication statusPublished - 15 Apr 2014

    Fingerprint

Keywords

  • Adsorption
  • Desorption
  • FeS
  • Mackinawite
  • Mercury
  • Ultrafiltration

ASJC Scopus subject areas

  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Ecological Modelling

Cite this