Removal of methylated arsenic in groundwater with iron filings

Publication Type  Journal Article
Year of Publication  2005
Authors  Cheng, Z. Q.; Van Geen, A.; Louis, R.; Nikolaidis, N.; Bailey, R.
Journal Title  Environmental Science & Technology
Volume  39
Issue  19
Pages  7662-7666
Journal Date  Oct 1
ISBN Number  0013-936X
Accession Number  ISI:000232410000051
Key Words  zero-valent iron; zerovalent iron; hydrous oxides; adsorption; kinetics; media; remediation; minerals; mobility; water

Field and laboratory experiments were conducted to study the potential use of Fe filings to remove monomethyl arsenate (MMA) and dimethyl arsenate (DMA) from contaminated waters. Batch experiments show that the affinity of MMA for Fe filings is comparable to that of inorganic arsenate, but lower than that for arsenite. In contrast, very little DMA was retained by Fe filings or their corrosion products. The wide range of affinities of different As species for Fe filings was confirmed by a series of retention and selective-leaching experiments using small columns and As-spiked groundwater. The effectiveness of Fe filings was also demonstrated with a field deployment at a U.S. Superfund site where groundwater is highly contaminated with both organic and inorganic As species. Over the course of 4 months, a 3 L cartridge of Fe filings removed > 85% of As contained in 16000 L of groundwater containing 1-1.5 mg/L total dissolved As, similar to 30% of which was organic As. The results indicate that Fe filings could be used to treat groundwater contaminated with MMA, which is the main organic form of As at most contaminated sites. Indications of partial demethylation in the column of Fe filings suggest conditions might be optimized further to enhance the removal of DMA.


971UJTimes Cited:8Cited References Count:22

URL  <Go to ISI>://000232410000051
DOI  Doi 10.1021/Es050429w