Arsenate immobilization associated with microbial oxidation of ferrous ion in complex acid sulfate water

Ma, Yingqun and Lin, Chuxia (2012) Arsenate immobilization associated with microbial oxidation of ferrous ion in complex acid sulfate water. Journal of Hazardous Materials, 217-21. pp. 238-245. ISSN 0304-3894

Abstract

Chemical, XRD, SEM, RS, FTIR and XPS techniques were used to investigate arsenate immobilization associated with microbial Fe2+ oxidation in a complex acid sulfate water system consisting of a modified 9 K solution (pH 2.0) plus As, Cu, Cd, Pb, Zn and Mn. At a 1:12.5:70 molar ratio of As:Fe:S, schweretmannite formation was impeded. This was in contrast with the predominant presence of schwertmannite when the heavy metals were absent, suggesting that a schwertmannite binding model is not valid for explaining arsenate immobilization in the complex system. In this study, arsenate was initially immobilized through co-precipitation with non-Fe metals and phosphate. Subsequently when sufficient Fe3+ was produced from Fe2+ oxidation, formation of a mixed iron, arsenate and phosphate phase predominated. The last stage involved surface complexation of arsenate species. Pb appeared to play an insignificant role in arsenate immobilization due to its strong affinity for sulfate to form anglesite. Phosphate strongly competed with arsenate for the available binding sites. However, As exhibited an increased capacity to compete with P and S for available binding sites from the co-precipitation to surface complexation stage. Adsorbed As tended to be in HAsO4 2− form. The scavenged arsenate species was relatively stable after 2464-h aging.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to published version due to publisher copyright policy (Elsevier).
Depositing User: Dr Chuxia Lin
Faculty / Department / School: Current - USQ Other
Date Deposited: 03 Sep 2012 12:20
Last Modified: 03 Jul 2013 01:08
Uncontrolled Keywords: arsenic; acid sulfate water; ochreous precipitate; co-precipitation; absorption
Fields of Research (FOR2008): 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040607 Surface Processes
05 Environmental Sciences > 0502 Environmental Science and Management > 050299 Environmental Science and Management not elsewhere classified
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9612 Rehabilitation of Degraded Environments > 961205 Rehabilitation of Degraded Mining Environments
Identification Number or DOI: doi: 10.1016/j.jhazmat.2012.03.021
URI: http://eprints.usq.edu.au/id/eprint/21072

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