N-TiO2-Coated SiC Foam for the Treatment of Dyeing Wastewater under Blue Light LED Irradiation

TiO2 is widely used for the photocatalytic degradation of organic pollutants in wastewater, but the practical applications of the photocatalyst are limited due to its poor visible light absorption and low recovery rate. In this study, high production of nitrogen-doped TiO2 was achieved by a hydrolysis precipitation method; the obtained N-TiO2 had a small crystallite size and good dispersibility. The effect of calcining temperature on the photocatalytic performance of N-TiO2 was evaluated through the degradation of methylene blue (MB) in a blue light LED irradiation cylinder, it was found the N-TiO2 calcined at 400 °C showed the best photocatalytic activity. Then the N-TiO2 was immobilized on SiC ceramic foam by dip-coating with PVA as the binder. The prepared N-TiO2/SiC foam showed excellent photocatalytic activity under blue light LED irradiation; as high as 96.3% of MB was degraded at optimum conditions. After five cycles of MB photodegradation, the photocatalytic activity of N-TiO2/SiC foam only changed slightly, which makes it a promising photocatalytic material for wastewater treatment.