PROCESSES OF FORMATION OF NH4- IONS DURING THE PHOTOCATALYZED OXIDATION OF N-CONTAINING COMPOUNDS AT THE TITANIA( AND NO3)WATER INTERFACE/

Nitrogen-containing substrates such as amino acids, amides, succinimid e, imidazole, hydroxylamine and urea were photodegraded in illuminated TiO2 suspensions, and the temporal course of formation of NH4+ and NO 3- ions was monitored. The hydroxylated nitrogen moiety in a molecule was predominantly converted to NO3- ions, whereas a primary amine and/ or an amide were exclusively transformed to NH4+ ions under the prevai ling conditions, Heterocyclic nitrogen groups in imidazole were conver ted to both NH4+ and NO3- ions via the intermediates whose structures were the primary amine and hydroxylamine, respectively, The influence of chemical structure on formation of NH4+ and NO3- ions is discussed from the view point of adsorption behaviours of substrates onto the Ti O2 surface.