Remediation of Arsenic Using Iron(III) Oxides

Arsenic is a toxin that occurs naturally in many water supplies due to aquifer geology. The EPA requires municipalities to meet a maximum of 10 ppb arsenic. Our study compares the effectiveness of natural and synthetic iron oxides for the remediation of ppb concentrations of arsenic. We studied natural and synthetic goethite, lepidocrocite, akaganéite, and hematite. These minerals were added to water samples containing 100 ppb arsenic. The treated sample was filtered and the remaining solution's arsenic concentration was determined using AAS-GF. XRD was used to confirm the mineralogy of the samples, and particle size analysis was used to normalize the results with respect to differing particle sizes. Differences in effectiveness were observed between natural and synthetic iron oxides with the latter most effective. These effects are likely due to differing particle sizes, mineral assemblages, or a combination of both factors. These plus a cost analysis will be presented.