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J Hazard Mater. 2009 Nov 15;171(1-3):980-6. doi: 10.1016/j.jhazmat.2009.06.102. Epub 2009 Jun 26.

X-ray absorption spectroscopy as a tool investigating arsenic(III) and arsenic(V) sorption by an aluminum-based drinking-water treatment residual.

Author information

1
Cyprus International Institute for the Environment and Public Health in Association with The Harvard School of Public Health, Nicosia 1105, Cyprus. kmakris@cyprusinstitute.org <kmakris@cyprusinstitute.org>

Abstract

Historic applications of arsenical pesticides to agricultural land have resulted in accumulation of residual arsenic (As) in such soils. In situ immobilization represents a cost-effective and least ecological disrupting treatment technology for soil As. Earlier work in our laboratory showed that drinking-water treatment residuals (WTRs), a low-cost, waste by-product of the drinking-water treatment process exhibit a high affinity for As. Wet chemical experiments (sorption kinetics and desorption) were coupled with X-ray absorption spectroscopy measurements to elucidate the bonding strength and type of As(V) and As(III) sorption by an aluminum-based WTR. A fast (1h), followed by a slower sorption stage resulted in As(V) and As(III) sorption capacities of 96% and 77%, respectively. Arsenic desorption with a 5mM oxalate from the WTR was minimal, being always <4%. X-ray absorption spectroscopy data showed inner-sphere complexation between As and surface hydroxyls. Reaction time (up to 48h) had no effect on the initial As oxidation state for sorbed As(V) and As(III). A combination of inner-sphere bonding types occurred between As and Al on the WTR surface because mixed surface geometries and interatomic distances were observed.

PMID:
19631458
DOI:
10.1016/j.jhazmat.2009.06.102
[Indexed for MEDLINE]

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