Enhanced photocatalytic discoloration of acid fuchsine wastewater by TiO2/schorl composite catalyst.

The existence of 'electrostatic poles' on the schorl surface encouraged us to apply schorl for a TiO(2) support. TiO(2)/schorl composite photocatalyst was prepared and characterized by XRD, SEM and UV/DRS, and their photocatalytic activity was evaluated by discoloration of acid fuchsine (AF). The results indicated that TiO(2) existed in the form of anatase and was well deposited and enwrapped on the schorl surface. The absorption edge of TiO(2)/schorl exhibited a slight red shift in the UV/DRS spectra, compared with that of pure TiO(2). The photocatalytic activity of TiO(2)/schorl for AF discoloration was higher than that of pure TiO(2). The AF discoloration ratio approached 100% after irradiation time of 12h. The optimum photocatalyst was found to be that containing 4.76 wt.% of schorl and sintered at 550 degrees C. The reaction followed pseudo-first-order kinetics, discussed by the Langmuir-Hinshelwood model. Hypotheses were proposed to interpret the mechanism for the enhanced photocatalytic activity of TiO(2)/schorl.