A comparison of 254 nm and 350 nm excitation of TiO 2 in simple photocatalytic reactors

Abstract

Photocatalytic reactors of simple annular design were manufactured from blacklight fluorescent tubes and germicidal tubes of identical dimensions and electrical power requirements. Salicylic acid and phenol selected as model water contaminants were analysed at various illumination times and TiO 2 loading conditions to determine degradation rates. The shorter wavelength 254 nm radiation is considerably more effective in promoting degradation than radiation centred at 350 nm and the optimum rate occurred with a lower catalyst loading than that required at 350 nm. However, even with 350 nm radiation, in oxygenated solutions containing 94 ppm of phenol and greater, the phenol was degraded at a rate of approximately 2400 ppm l −1 kWh −1 and was mineralized at the equivalent of 820 ppm total organic carbon destroyed l −1 kWh −1. Phenol and Degussa P25 TiO 2 catalyst provide a basis for future comparative photocatalytic reactor performance evaluations.