- Title
- Sorption of Arsenic(V) and Arsenic(III) to schwertmannite
- Creator
- Burton, Edward; Bush, Richard; Johnston, Scott; Watling, Kym; Hocking, Rosalie; Sullivan, Leigh; Parker, Gretel
- Date
- 2009
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/99498
- Identifier
- vital:10373
- Identifier
-
https://doi.org/10.1021/es902461x
- Identifier
- ISSN:0013-936X
- Abstract
- This study describes the sorption of As(V) and As(III) to schwertmannite as a function of pH and arsenic loading. In general, sorption of As(V) was greatest at low pH, whereas high pH favored the sorption of As(III). The actual pH of equivalent As(V) and As(III) sorption was strongly loading dependent, decreasing from pH ∼ 8.0 at loadings <120 mmolAs mol Fe -1 to pH ∼ 4.6 at a loading of 380 mmolAs molFe -1. Sorption isotherms for As(V) were characterized by strong partitioning to the schwertmannite solid-phase at low loadings and sorption capacities of 225-330 mmolAs(V) molFe -1 at high loadings. In contrast, the As(III) isotherms revealed a weak affinity for sorption of As(III) versus As(V) at low loadings yet a greater affinity for As(III) sorption compared with As(V) at high loadings (when pH > 4.6). Sorption of As(V) and As(III) caused significant release of SO 4 2- from within the schwertmannite solid-phase, without major degradation of the schwertmannite structure (as evident by X-ray diffraction and Raman spectroscopy). This can be interpreted as arsenic sorption via incorporation into the schwertmannite structure, rather than merely surface complexation at the mineral-water interface. The results of this study have important implications for arsenic mobility in the presence of schwertmannite, such as in areas affected by acidmine drainage and acid-sulfate soils. In particular, arsenic speciation, arsenic loading, and pH should be considered when predicting and managing arsenic mobility in schwertmanniterich systems. © 2009 American Chemical Society.
- Publisher
- ACS Publications
- Relation
- Environmental Science and Technology Vol. 43, no. 24 (2009), p. 9202-9207
- Rights
- Copyright © 2009 American Chemical Society.
- Rights
- This metadata is freely available under a CCO license
- Subject
- MD Multidisciplinary; Acid mine drainage; Arsenic mobility; Arsenic sorption; Arsenic speciation; High loadings; High pH; Low loading; Mineral-water interface; Schwertmannite; Solid-phase; Sorption capacities; Sorption isotherms; Sulfate soils; Surface complexation
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