Electrochemical Remediation of Arsenic and Chromium

Schematic of arsenic removal using zero-valent iron media.

Background
Although laboratory investigations have demonstrated the short-term effectiveness of zerovalent iron for mediating the reductive precipitation of chromium and arsenic compounds, the long-term effectiveness of the process has not been established, and the conditions favoring arsenic and chromium removal are not well understood.

Goal
To investigate the effects of water chemistry, surface precipitate buildup and iron surface aging on arsenic and chromium removal from contaminated waters by zerovalent iron and to investigate arsenic and chromium removal via electrosorption and reduction by anodically polarized magnetite.

Objectives
1) To determine if zero valent iron is effective for arsenic and chromium removal in above ground canister remedial systems.

2) To determine the long-term effectiveness of zero valent iron for arsenic and chromium removal in in-situ permeable barrier configurations.

3) To determine the effectiveness of anodically polarized magnetite for removing arsenic and chromium oxyanions from contaminated waters.

Significant Findings
1. Mechanistically based kinetic models have been developed to describe arsenic and chromium removal in flow-through systems.

2. In addition to elucidating the removal mechanisms, we have also investigated how the co-contaminants, trichloroethylene and nitrate, affect arsenic and chromium removal. Application of this knowledge will aid in the development of the emerging permeable reactive barrier technology for in situ treatment of contaminated groundwater.

Publications

Contact
James Farrell
farrellj@engr.arizona.edu
520-621-2465