Photocatalytic degradation (PCD) of NH3, alkylamines, and alkylammoniums was systematically studied in aerated and deaerated aqueous suspensions of pure or modified titania. While the slow photocatalytic oxidation of NH3 to nitrite/nitrate was the only pathway for decomposition of NH3 on naked TiO2, a new pathway, that of selective oxidation of NH3 to dinitrogen, opened up on Pt/TiO2. The PCD of tetramethylammoniums on TiO2 showed successive demethylation processes to generate tri-, di-, and mono-methylammonium as an intermediate and ammonium and nitrate as a final product in the presence of dissolved oxygen, but it did not take place without oxygen. However, the absence of dissolved oxygen increased the PCD rates of alkylamines on Pt/TiO2, and generated products that were different from those formed on pure TiO2. Alkylamine degradation using surface-fluorinated TiO2 or silica-modified TiO2 photocatalyst was discussed. This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA 8/22-26/2004).
ASJC Scopus subject areas
- Chemical Engineering(all)