Electrochemical reduction of selenate using reactive anode

The removal of selenate, Se(VI), was investigated in a batch electrochemical system using reactive iron anode. Ferrous hydroxide played an important role for the removal of Se(VI) when an iron anode was used, but mixed metal oxide anode was not effective in removing Se(VI). The iron anode produces a greater (negative) decrease in the oxidation-reduction potential because it replaces the generation of oxygen gas with production of ferrous ions at the anode. Pure ferrous hydroxide removed Se(VI), however, the rate was very slow. The removal rates range from 45.1% to 97.4% with rate constants ranging from 0.104 h-1 to 0.548 h-1. The rates were optimized at lower initial concentrations, higher electrical currents, and the presence of iron. Dissolved oxygen affected the removal of Se(VI) only slightly. Based on the experimental results, Se(VI) transformation or removal can be achieved using electrolysis with reactive iron anode.