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Arsenic remediation by formation of arsenic sulfide minerals in a continuous anaerobic bioreactor

Lookup NU author(s): Dr Lucia Rodriguez Freire


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Arsenic (As) is a highly toxic metalloid that has been identified at high concentrations in groundwater in certain locations around the world. Concurrent microbial reduction of arsenate (AsV) and sulfate (SO42−) can result in the formation of poorly soluble arsenic sulfide minerals (ASM). The objective of this research was to study As biomineralization in a minimal iron environment for the bioremediation of As-contaminated groundwater using simultaneous AsV and SO42− reduction. A continuous-flow anaerobic bioreactor was maintained at slightly acidic pH (6.25–6.50) and fed with AsV and SO42−, utilizing ethanol as an electron donor for over 250 d. A second bioreactor running under the same conditions but lacking SO42− was operated as a control to study the fate of As (without S). The reactor fed with SO42− removed an average 91.2% of the total soluble As at volumetric rates up to 2.9 mg As/(L · h), while less than 5% removal was observed in the control bioreactor. Soluble S removal occurred with an S to As molar ratio of 1.2, suggesting the formation of a mixture of orpiment- (As2S3) and realgar-like (AsS) solid phases. Solid phase characterization using K-edge X-ray absorption spectroscopy confirmed the formation of a mixture of As2S3 and AsS. These results indicate that a bioremediation process relying on the addition of a simple, low-cost electron donor offers potential to promote the removal of As from groundwater with naturally occurring or added SO42− by precipitation of ASM.

Publication metadata

Author(s): Rodriguez-Freire L, Moore SE, Sierra-Alvarez R, Root RA, Chorover J, Field JA

Publication type: Article

Publication status: Published

Journal: Biotechnology and Bioengineering

Year: 2016

Volume: 113

Issue: 3

Pages: 522-530

Print publication date: 01/03/2016

Online publication date: 02/09/2015

Acceptance date: 23/08/2015

ISSN (print): 0006-3592

ISSN (electronic): 1097-0290

Publisher: John Wiley & Sons, Inc.


DOI: 10.1002/bit.25825


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