Electrocoagulation study for the removal of arsenic and chromium from aqueous solution.

This study was undertaken to investigate the removal of arsenic (As) and chromium (Cr) from aqueous solution using electrocoagulation (EC) technique. Batch EC studies were performed using iron electrodes to evaluate the influence of various experimental parameters on the removal of metal ions. The parameters were initial pH (pH(0)), electrolysis time (t), initial concentration (C(0)), electrode gap (g), stirring rate (r) and current density (j). Effect of pH(0) was studied in the range 2.0 to 8.0 while C(0) was varied from 10 to 100 mg/L. As and Cr removal by EC was governed by the chemical dissolution of iron, and the formation of metal-hydrous ferric oxide complexes, which in turn was strongly, influenced by pH(0) and j. Optimum value of pH(0) and j for As and Cr removal were found to be 4.0 and 2.0; and 75 and 50 A/m(2), respectively. Removal efficiency increased with decrease in the value of C(0) and g. The r value of 100 rpm produced sufficient agitation for the proper agglomeration of flocs and optimum removal of ions.