Journal article
Sorption of arsenic(V) and arsenic(III) to schwertmannite
Environmental Science and Technology, Vol.43(24), pp.9202-9207
2009
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Abstract
<p>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 molFe−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 SO42− 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 acid-mine drainage and acid-sulfate soils. In particular, arsenic speciation, arsenic loading, and pH should be considered when predicting and managing arsenic mobility in schwertmannite-rich systems.</p>
Details
- Title
- Sorption of arsenic(V) and arsenic(III) to schwertmannite
- Creators
- Edward D Burton - Southern Cross UniversityRichard T Bush - Southern Cross UniversityScott G Johnston - Southern Cross UniversityKym M Watling - Southern Cross UniversityRosalie K Hocking - Monash UniversityLeigh A Sullivan - Southern Cross UniversityGretel K Parker - Griffith University
- Publication Details
- Environmental Science and Technology, Vol.43(24), pp.9202-9207
- Identifiers
- 1576; 991012822004102368
- Academic Unit
- Science; School of Environment, Science and Engineering; Southern Cross GeoScience; Faculty of Science and Engineering
- Resource Type
- Journal article