Effect of ferrous iron on arsenate sorption to amorphous ferric hydroxide

Muhammed Mukiibi, Wendell P. Ela, A. Eduardo Sáez

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations


Amorphous ferric hydroxide (AFH) sorbents are commonly used for removal of arsenate from water. When disposed in microbially active, reducing environments, such as landfills, Fe(II) will be generated by reductive dissolution of the AFH surface and arsenate will be desorbed. However, the observed ratio of arsenate (and, in fact, total arsenic) to total iron in the leachate is not consistent with the original ratio of arsenate to iron on the AFH. Work to determine if ferrous iron re-adsorption to the AFH can partially explain this inconsistency is described. As pH increases above 7, Fe(II) increasingly sorbs onto the AFH surface. This sorption is largely independent of ionic strength and somewhat irreversible at high pH. In contrast, arsenate partitioning to AFH decreases with increasing pH. However, over the pH range from 5 to 9, the presence of Fe(II) sorbed to the AFH surface increases the capacity for arsenate sorption. In addition, when no Fe(II) is present, arsenate binding is largely to surface sites inaccessible to Fe(II) binding. The results are also consistent with Fe(II) sorption to AFH sites, otherwise unfavorable to arsenate binding and transformation of those sites into arsenate-amenable binding sites.

Original languageEnglish (US)
Title of host publicationEnvironmental Challenges in the Pacific Basin
PublisherBlackwell Publishing Inc.
Number of pages11
ISBN (Print)9781573317405
StatePublished - Oct 2008

Publication series

NameAnnals of the New York Academy of Sciences
ISSN (Print)0077-8923
ISSN (Electronic)1749-6632


  • ABSR
  • Amorphous ferric hydroxide
  • Arsenate
  • Arsenic residuals disposal
  • As(V)
  • Fe(II)
  • Ferrous iron
  • Sorption
  • Water treatment residuals

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • History and Philosophy of Science


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