Preparation of mesoporous tourmaline / TiO₂ composites and their simulated sunlight photocatalytic activity

A series of mesoporous tourmaline/TiO₂ composites were prepared by using one-step sol-gel co-condensation combined with solvothermal synthesis technique, and their phase structure, morphology, porosity, optical absorption property, as well as composition and structure were characterized. The results show that the tourmaline/TiO₂ composites exhibit pure anatase crystalline phase, uniform mesostructure, large surface area (205-242 m²·g^-1), uniform pore size distribution (3.4-3.8 nm) and low band gap energy (3.0 eV). The as-prepared composites were successfully applied to the degradation of aqueous organic pollutants rhodamine B and norfloxacin under simulated sunlight irradiation. The degradation kinetics researches show that, the addition of tourmaline improves the photocatalytic quantum efficiency of TiO₂ and reduces the band gap energy of TiO₂. The composites with 1wt%-5wt% tourmaline loading exhibit the higher rates to the rhodamine B degradation and the degradation rates of tourmaline/TiO₂ composites to the norfloxacin are higher than that of the pure TiO₂.