Temperature-Controlled Synthesis of TiO2 Photocatalyst with Different Crystalline Phases and Its Photocatalytic Activity in the Degradation of Different Mixed Dyes

A polyacrylamide gel method was explored to create heterojunction between anatase and rutile TiO2 with high optical absorption coefficient in the ultraviolet region. Sintering temperature played a pivotal role in controlling the phase purity, surface morphology, optical properties and photocatalytic activity. The anatase and rutile mixed TiO2 and a single-phase rutile TiO2 applied in photocatalytic treatment of simulated industrial dye-contaminated wastewater containing methyl red (MR) + methylene blue (MB) + methyl orange (MO) + congo red (CR) + rhodamine B (RhB), degradation under ultraviolet light irradiation. The anatase and rutile mixed TiO2 photocatalyst exhibited a higher photocatalytic activity in rapid degradation of simulated industrial dye wastewater under ultraviolet light irradiation than that of the single-phase rutile TiO2 particles. The anatase and rutile mixed TiO2 and a single-phase rutile TiO2 photocatalyst showed selective photocatalysis in the case of simulated industrial dye wastewater. For the anatase and rutile mixed TiO2 photocatalyst, MR in the mixed dyes was the most rapidly photodegraded. Based on the analysis of the experimental results, a possible photocatalytic mechanism was proposed.