Photocatalytic Treatment of Different Types of High−Concentration Ammonia Wastewater by Cu/TiO2 Film and its Mechanism Study

Abstract

Photocatalytic oxidation of ammonia in wastewater has been abundantly investigated in lab − scale, but there are still many issues to be solved towards practical application. Herein, we have immobilized Cu/TiO2 photocatalyst on different solid substrates in order to practically utilize and recycle the photocatalyst during wastewater treatment, on the basis of exploring the effects of different influencing factors such as pH, temperature and salinity on the photocatalytic oxidation of ammonia in this work. The performance of Cu/TiO2 films was evaluated by circulated treatment of different types of wastewater including high salinity ammonia wastewater, copper − ammonia wastewater and liquid − ammonia mercerization wastewater. The characters of wastewater matrices significantly influence the performance for ammonia oxidation. Different from the slurry test of photocatalyst power that operated in a closed reactor, it is importantly found that oxygen in air plays significant role in photocatalytic oxidation of ammonia into dinitrogen in the aerobic oxidation process, when the Cu/TiO2 films were employed. The possible oxidation mechanism has been proposed to elucidate the ammonia oxidation process.