Removal of Cr(VI) with Cogeneration of Electricity by an Alkaline Fuel Cell Reactor

Electricity can be harvested directly from an alkaline ethanol fuel cell (AEFC) reactor in which contaminant Cr(VI) is taken as the oxidant. The performance of the AEFC reactor was characterized in terms of power generation, Cr(VI) removal, cathodic efficiency, polarization curves, and Cr(VI) reduction kinetics. The cell potential, Cr(VI) removal, and cathodic efficiency are strongly dependent on pH and Cr(VI) concentration. Using 3.94 mM Cr(VI) in 1 M H 2 SO 4 catholyte and 2.0 M C 2 H 5 OH in 0.5 M KOH anolyte, a high open circuit potential of 1.46 V and more than 96.0% Cr(VI) removal efficiency could be achieved, and in case of varying Cr(VI) concentration to 8.65 mM, a power density of 0.19 mW cm –2 at a current density of 0.23 mA cm –2 was observed. The Cr(VI) reduction follows a first-order kinetics. This work shows that the use of fuel cell provides a novel approach for simultaneous electricity generation and contaminant abatement.