DEPENDENCE ON CHEMICAL-STRUCTURE OF THE PRODUCTION OF NH4- IONS DURING THE PHOTOCATALYZED OXIDATION OF NITROGEN-CONTAINING SUBSTANCES AT THE TITANIA WATER INTERFACE( AND OR NO3)

The dependence of the formation of NH4+ and/or NO3- ions on chemical s tructure has been examined in TiO2 photocatalyzed oxidations of variou s amino acids, amides, and nitrogen-heterocyclic compounds. The primar y amino groups and the amide moiety are converted photocatalytically a nd predominantly to NH4+ ions, whereas the hydroxylamino group in N-hy droxysuccinimide is photoconverted predominantly to NO3- ion. Results show that the nitrogen at the 1-position in imidazole is mainly photoc onverted to NH4+ ion by analogy with the equivalent nitrogen atom in p yrrole; the nitrogen at the 3-position is transformed into NO3- ion. F ormation of ammonium ions is faster than formation of nitrate ions in all but the N-hydroxysuccinimide substrate.