Photoelectrocatalytic degradation of 4,4′-dibromobiphenyl in aqueous solution on TiO2 and doped TiO2 nanotube arrays

Polybrominated biphenyls have been widely used as flameretardants in textile and electronic industries, and additives in plastics. Over the past few decades, much attention has been given to polybrominated biphenyls in the environment and their effects on humans. In this paper, we studied on the degradation of 4,4′-dibromobiphenyl, a typical one of polybrominated biphenyls, through photoelectrocatalytic process with TiO2, Zr/TiO2 and Zr, N/TiO2 nanotube arrays. The results showed that the photoelectrocatalytic process was more efficient than photocatalytic and electrolytic process alone. The results exhibited that the photoelectrocatalytic efficiency was significantly affected by the properties of the catalysts and bias potential, and the highest photoelectrocatalytic degradation rate was achieved with Zr, N/TiO2 at 1 V and the order was Zr, N/TiO2 > Zr/TiO2 > TiO2. The mechanism was also discussed by detecting the changes of pH value, bromine anion, total organic carbon and intermediates during the process.