Removal of Methylated Arsenic in Groundwater with Iron Filings

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• 作者：Zhongqi Cheng ; Alexander Van Geen ; Roseline Louis ; Nikolaos Nikolaidis ; and Richard Bailey
• 刊名：Environmental Science & Technology
• 出版年：2005
• 出版时间：October 1, 2005
• 年：2005
• 卷：39
• 期：19
• 页码：7662 - 7666
• 全文大小：238K
• 年卷期：v.39,no.19(October 1, 2005)
• ISSN：1520-5851

文摘

Field and laboratory experiments were conducted tostudy the potential use of Fe filings to remove monomethylarsenate (MMA) and dimethyl arsenate (DMA) fromcontaminated waters. Batch experiments show that theaffinity of MMA for Fe filings is comparable to that of inorganicarsenate, but lower than that for arsenite. In contrast,very little DMA was retained by Fe filings or their corrosionproducts. The wide range of affinities of different Asspecies for Fe filings was confirmed by a series of retentionand selective-leaching experiments using small columnsand As-spiked groundwater. The effectiveness of Fe filingswas also demonstrated with a field deployment at a U.S.Superfund site where groundwater is highly contaminatedwith both organic and inorganic As species. Over thecourse of 4 months, a 3 L cartridge of Fe filings removed>85% of As contained in 16000 L of groundwater containing1-1.5 mg/L total dissolved As, ~30% of which wasorganic As. The results indicate that Fe filings could beused to treat groundwater contaminated with MMA, whichis the main organic form of As at most contaminatedsites. Indications of partial demethylation in the column ofFe filings suggest conditions might be optimized furtherto enhance the removal of DMA.