Photocatalytic degradation of 3,4-dichlorophenylurea in aqueous gold nanoparticles-modified titanium dioxide suspension under simulated solar light.

The TiO(2) modified with nanosized gold particles was prepared by deposition-precipitation at pH 7 and calcination in air at various temperatures up to 973 K. The materials were characterized by transmission electron microscope, X-ray diffraction spectrometry, and atomic absorption spectroscopy. The highest photocatalytic efficiency was obtained at the calcination temperature of 873 K. The decrease in 3,4-dichlorophenylurea concentration follows first order kinetics with a half life of 36.6 ± 2.0 min in 100 mg L(-1) of 0.83 wt% Au/TiO(2). Fifteen degradation products were identified using LC/MS/MS and IC. Degradation pathway was proposed on the basis of the observed transformation products.