Nano TiO₂ Deposited on Crude Mineral and the Photoactivity to the Degradation of Chloroform

Supported TiO₂ catalysts have increasingly attracted intention in recent years because of their potential application to photocatalytic degradation of organic pollutants in water and air. In this work, nano TiO₂ particles deposited on crude nonmetallic mineral were prepared by a Sol-gel process, the photocatalyst for degradation of chloroform was tested and optimized with respect to TiO₂ loading, catalyst dosage and pH value of the initial wastewater. The adsorption property and photocatalytic activity of the as-prepared catalysts were investigated with chloroform as a probe molecule. A maximum photodegradation yield of chloroform (67%) on catalyst TiO2/diatomite was obtained, under conditions of about 75-wt% of TiO₂ loading, 0.2 g L^-1 TiO₂ dosage and pH=6~8 in the initial wastewater. The measurement of chloroform adsorbed on the catalysts reveals that the high activity of the catalyst TiO₂/diatomite is attributed to the relatively high adsorption strength of the diatomite, on which a fairy high amount of adsorbed chloroform was available and was mobile under the presence of the concentration gradient around the TiO₂ particles.