Heterogeneous photocatalytic degradation of ethylene glycol and propylene glycol

The photocatalytic decomposition of ethylene glycol and propylene glycol was investigated by using UV-illuminated TiO2 and metal-loaded TiO2 catalysts. The effects of pH, initial concentration, and wavelength of light on the decomposition rate of the glycols were explored. Platinum- and palladium-loaded TiO2 catalysts enhanced the rates of photodecomposition compared to unloaded TiO2. The glycols were oxidized primarily to carbon dioxide and water. Formaldehyde was found to be an important reaction intermediate. A detailed chemical reaction mechanism for the destruction of ethylene glycol and propylene glycol in water via free radical pathway and trapped bole reactions at the particle surface is proposed.