A newly developed slurry-type titanium dioxide (TiO
2) photocatalyst has been applied to the decomposition of pesticides in water. This photocatalyst is composed of the TiO
2 nanoparticles deposited on the surface of a zeolite. Kinetic studies were performed on the photocatalytic decomposition using atrazine as the model pesticide. Reaction rate constants of 0.123, 0.161, and 0.512 min
−1 for the TiO
2 concentrations in the TiO
2/zeolite complex of 0.025, 0.050, and 0.250 g/L, respectively, were obtained using an ultraviolet light source of 1 mW/cm
2 at a wavelength of 350 nm. This showed that as the concentration of the TiO
2 particles increased, the reaction rate constant also increased. In the prototype apparatus study, the concentration of atrazine in the treated water was maintained at 10 μg/L. Bubbling oxygen in the photoreactor was found to facilitate the decomposition of pesticides, indicating that the diffusion of oxygen gas on the TiO
2 surface is the rate-determining step in the overall reaction process. The electric energy per order (E
EO) under high oxygen concentration was 0.159 kWh/m
3/order, which is comparable to other treatment methods.
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