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Groundwater arsenic remediation using zerovalent iron: Batch and column tests
Citation:
SU, C. AND R. PULS. Groundwater arsenic remediation using zerovalent iron: Batch and column tests. Presented at Institure of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, CHINA, April 21 - 26, 2010.
Impact/Purpose:
The purpose is to continue studies which are needed to improve the technology for both in situ and ex situ arsenic removal from ontaminated water.
Description:
Recently, increasing efforts have been made to explore the applicability and limitations of zerovalent iron (Fe0) for the treatment of arsenicbearing groundwater and wastewater. The experimental batch and column tests have demonstrated that arsenate and arsenite are removed effectively from aqueous solution using Fe0. Arsenic removal efficacy depends on the type of Fe0, surface area and corrosion rate of the Fe0, and water chemistry. Enhanced corrosion of Fe0 in the presence of dissolved oxygen leads to an increase in surface area of the Fe0 from pitting and neoformation of iron oxides and green rusts, which leads to greater arsenic removal. The iron-arsenic precipitates produced in the Fe0 system seem to be stable in solution and the precipitation process seems to be irreversible. Possible mechanisms for arsenic removal in the Fe0 systems include surface adsorption, precipitation, co-precipitation, and redox transformation. Although experimental results are encouraging so far, there are still various gaps in the knowledge pertaining to detailed mechanisms of arsenic removal, to long-term stability of sequestered arsenic in the Fe0 system, and to field-scale application of Fe0. Further studies are needed to improve the technology for both in situ and ex situ arsenic removal from contaminated water.