Photocatalytic destruction of phenol and salicylic acid with aerosol-made and commercial titania powders

The photocatalytic destruction of phenol and salicylic acid in aerated aqueous suspensions of titania powders made in flame reactors was studied. These powders were made in five hydrocarbon diffusion flames by hydrolysis and oxidation of TiCl4 that resulted in powders of high specific surface area and high anatase content. The photoactivity of the flame-made titania powders was comparable and slightly better to that of commercial Degussa P25. Doping the titania with SiO2 was detrimental to the photoactivity of the powders in contrast with what was seen in non-aerated suspensions. The photodegradation of phenol followed a first-order law while the Langmuir-Hinshelwood model was found to most accurately represent the photodegradation of salicylic acid.