What’s the Best Way to Iron Out Your Hexavalent Chromium? Ferrous Sulfate versus Zero-Valent Iron(Abstract)

摘要

A bench-scale treatability study was conducted to evaluate using granular, micro- scale, and nanoscale zero valent iron (ZVI) products and ferrous sulfate (FeSO4) to reduce hexavalent chromium (Cr~(6+)) to trivalent chromium (Cr~(3+)) in both soil and groundwater at a site where chrome plating operations were previously conducted. Based on the bench-scale study, a treatment was selected and used in a full-scale field applica- tion to reduce concentrations of Cr~(6+) in site soil (194 mg/kg) and groundwater (580 mg/L). Microcosms were constructed with site soil and groundwater. A total of 10 soil treat- ments were constructed: an active control; microscale ZVI at 0.1%, 1%, and 10% mass to mass (m:m); granular ZVI at 0.1%, 1%, and 10% m:m; and FeSO4 at 0.05%, 0.5%, and 1% m:m. A total of three groundwater treatments were constructed: an active control, nanoscale ZVI at 10 g/L, and FeSO4 at 18.6 g/L. The m:m ratio and groundwater treat- ment concentrations were based on the mass of iron required to achieve the desired reduction of Cr~(6+) as measured in the baseline sample.