Synchronous organics removal and copper reduction in semiconductor wastewater with energy recuperation via photocatalytic fuel cell

Abstract

An effective PFC constructed from ZnO/Zn photoanode and carbon cloth cathode has been proposed to oxidatively degrade organics and reductively treat Cu (II) in the semiconductor wastewater accompanied with electricity production. The cell electrical performance with open circuit voltage of 835 V, maximum power density of 0.003623 mW cm-2 and short circuit current density of 0.0506 mA cm-2 can be obtained using optimized catalyst loading of 1.0 g L-1 and semiconductor wastewater concentration of 10 mg L-1. Under the optimal test, more photogenerated electrons will be facilitated for charge carrier separation in the photoanode, accelerating the organics degradation on anode, and subsequently the electron migrating to cathode for Cu (II) reduction. A complete mineralization with 10 mg L-1 COD and more than 70% Cu (II) removal efficiency can be attained within 180 min. A good reproducibility test has been also witnessed because of the stable photoanode and cathode materials. This work may pave an effective and sustainable approach to concurrently eliminate two kinds of contaminants with energy recuperation in a single chamber.