Characterizing As(III, V) adsorption by soils surrounding ash disposal facilities

Perre E. Burns, Seunghun Hyun, Linda S. Lee, Ishwar Murarka

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Leachate derived from unlined coal ash disposal facilities is a potential anthropogenic source of arsenic to the environment. To establish a theoretical framework for predicting attenuation of arsenic by soils subject to ash landfill leachate, which is typically enriched in calcium and sulfate, the adsorption of As(V) and As(III) was characterized from 1 mM CaSO4 for 18 soils obtained down-gradient from three ash landfill sites and representing a wide range in soil properties. As(V) consistently exhibited an order of magnitude greater adsorption than As(III). As(V) adsorption was best described by coupling pH with 15 s DCB-Fe (R2 = 0.851, α = 0.001), although pH coupled to clay, DCB-Fe, or DCB-Al also generated strong correlations. For As(III), pH coupled to Ox-Fe (R2 = 0.725, α = 0.001) or Ox-Fe/Al (R2 = 0.771, α = 0.001) provided the best predictive relationships. Ca2+ induced increases in As(V) adsorption whereas sulfate suppressed both As(V) and As(III) adsorption. Attenuation of arsenic from ash leachate agreed well with adsorption measured from 1 mM CaSO4 suggesting that the use of 1 mM CaSO4 in laboratory adsorption tests is a reasonable approach for estimating arsenic behavior in soils surrounding ash landfills. We also showed that the impact of leachate-induced changes in soil pH over time may not be significant for As(V) adsorption at pH < 7; however, As(III) adsorption may be impacted over a wider pH range especially if phyllosilicate clays contribute significantly to adsorption. The benefits and limitations of predicting arsenic mobility using linearized adsorption coefficients estimated from nonlinear adsorption isotherms or from the relationships generated in this study are also discussed.

Original languageEnglish
Pages (from-to)1879-1891
Number of pages13
JournalChemosphere
Volume63
Issue number11
DOIs
Publication statusPublished - 2006 Jun
Externally publishedYes

Keywords

  • Adsorption
  • Arsenic
  • Coal ash leachate
  • Natural attenuation
  • Retardation

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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