USING LOW CURRENT DENSITY ARSENIC ELECTROCOAGULATION KINETICS TO MODEL MICROBIALLY MEDIATED ARSENIC ELECTROCOAGULATION

Many areas of Switzerland contain high concentrations of geogenic arsenic in groundwater. In the Valais Canton, approximately 12,000 people live in areas where concentrations of As in groundwater exceed WHO recommendations of 10μg/L. As such is the case, novel arsenic removal techniques are needed to ensure the general health of Swiss residents. This experiment investigated electrocoagulation as a potential aqueous arsenic mitigation method in Switzerland. Ten electrocoagulation experiments (1-10mA/cm) were carried out in iron (N=2) and aluminum (N=8) electrode bearing electrocoagulation cells to model the efficiency of removing arsenic species from water at low current density. The electrocoagulation cells contained arsenic species at either 6.6mM As(III) or 6.6 mM As(V) and the total amounts of arsenic removed from cells in time was measured through ICP-OES.

Results from this study indicate that removal efficiency of arsenic from within cells is dependent upon electrode material and current density. There are similar removal rates in time for As(III) and As(V) containing electrocoagulation cells per current density at low current densities. Furthermore, electrocoagulative Arsenic mitigation rates show that iron electrode electrocoagulation cells are approximately (41%) more efficient than aluminum electrocoagulation cells for total arsenic removal per amount of current passed through solution. These experimental results provide a model of comparison for the introduction of bacteria with extracellular electron transferring metabolic processes into electrocoagulation cells. Future experiments will be run in microbially mediated electrocoagulation cells to investigate the effects of in-situ electrotrophic microbial culture on the efficiency of electrocoagulative arsenic removal at low current density.