Fig. 4From: The performance of Cu2+ as dissolved cathodic electron-shuttle mediator for Cr6+ reduction in the microbial fuel cella Temporal behavior of Cr6+ and Cu2+ and corresponding change in the pH value at pH 4; b Cyclic voltammograms of CC electrode in Cu2+, Cr6+, and Cr6+ & Cu2+ mediated solution at pH 4Back to article page