Synthesis and visible light photoactivity of anatase Ag and garlic loaded TiO2 nanocrystalline catalyst

An excellent visible light activated Ag and garlic loaded TiO2 nanocatalyst was prepared by using AgNO3 and garlic (Allium sativum) as the Ag+ and sulfur sources, respectively. The catalyst resisted the change from anatase to rutile phase even at high (700 degrees C) calcination temperature. The photocatalytic efficiency of as-prepared nanocatalysts was evaluated by degrading (100 ppm) azodye, methyl orange (MO), and dichloro phenol (DCP) under visible light irradiation for 3 to 4 h from an incandescent light bulb (300 W). The process followed first order reaction kinetics with reaction rates ranging from 9.5 x 10(-4) to 19.4 x 10(-3) min(-1). The dye was decomposed in 3 h and more than 70% DCP degraded in 4 h in the presence of Ag and garlic loaded-TiO2 calcined at 700 degrees C. Demineralization of the solution was in the range 40 to 90%. A complete elimination of Vibrio fischeri was accomplished with 1 mg L-1 of nanocatalyst regardless the calcination temperature. The catalyst was used for up to 5 consecutive runs without the significant loss in the photocatalytic activity and could be regenerated by adopting a simple procedure of washing with water and acetone as well as drying at 200 degrees C for 2 h.