Synergistic photocatalytic degradation of pyridine using precious metal supported TiO₂ with KBrO₃

A series of precious metals catalysts (M/TiO₂, M = Ru, Rh, Pd, Ag, Ir, Pt or Au) were prepared by a light deposition method and the synergistic photocatalytic degradations of pyridine (20 mg/L) under UV irradiation (365 nm) using M/TiO₂ with electron capture agent KBrO3 have been investigated. The results show that KBrO3 has a greatly synergistic role on M/TiO2 and the photocatalytic activity of M/TiO2 is closely related to its work function. Ag could greatly enhance the activity of TiO2 due to the binding characteristics of pyridine on Ag. Under the conditions of 0.5 wt.% Ag loading, Ag/TiO2 concentration of 0.1 g/L, KBrO3 concentration of 10 mmol/L and reaction liquid pH value at 9, the pyridine can be degraded by 64% within 3 hr, doubled than TiO₂ photocatalytic system. The degradation kinetics of pyridine follows first-order kinetics and k = 5.53 × 10^-3 min^-1.