Arsenic re-mobilization in water treatment adsorbents under reducing conditions: Part II. XAS and modeling study

Suqin Liu, Chuanyong Jing, Xiaoguang Meng

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The mechanism of arsenic re-mobilization in spent adsorbents under reducing conditions was studied using X-ray absorption spectroscopy and surface complexation model calculations. X-ray absorption near edge structure (XANES) spectroscopy demonstrated that As(V) was partially reduced to As(III) in spent granular ferric hydroxide (GFH), titanium dioxide (TiO2), activated alumina (AA) and modified activated alumina (MAA) adsorbents after 2 years of anaerobic incubation. As(V) was completely reduced to As(III) in spent granular ferric oxide (GFO) under 2-year incubation. The extended X-ray absorption fine structure (EXAFS) spectroscopy analysis showed that As(III) formed bidentate binuclear surface complexes on GFO as evidenced by an average As(III)-O bond distance of 1.78 Å and As(III)-Fe distance of 3.34 Å. The release of As from the spent GFO and TiO2 was simulated using the charge distribution multi-site complexation (CD-MUSIC) model. The observed redox ranges for As release and sulfate mobility were described by model calculations.

Original languageEnglish
Pages (from-to)137-144
Number of pages8
JournalScience of the Total Environment
Volume392
Issue number1
DOIs
StatePublished - 15 Mar 2008

Keywords

  • Arsenic
  • CD-MUSIC model
  • EXAFS
  • Re-mobilization
  • XANES

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