Industrial Coke as an Electrode Material for Environmental Remediation

Abstract

Industrial coke was evaluated as a low-cost electrode material for environmental remediation, using the dye Orange II as an example substrate. Coke was used as massive pieces in batch cells or in the ground form for use in a packed-bed reactor. The loss of Orange II was faster when the supporting electrolyte contained chloride ion, and under these conditions the reaction involved hypochlorination. In the batch reactor, the current efficiency for mineralization was only modest (4−14%). In the packed-bed reactor, the loss of both starting material and intermediates was fastest at high current and low flow rate, and a near-quantitative current efficiency was achieved. The high current efficiency was explained by the greater surface area of the electrodes in the packed-bed reactor compared with the batch reactor, and better contact between the solution to be remediated and the coke particles. A drawback to the use of coke electrodes for the remediation of aqueous wastes is their tendency to increase the total organic carbon content of an aqueous solution, especially under anodic polarization