FORMATION OF NITRATE AND AMMONIUM-IONS IN TITANIUM-DIOXIDE MEDIATED PHOTOCATALYTIC DEGRADATION OF ORGANIC-COMPOUNDS CONTAINING NITROGEN-ATOMS

The photocatalytic oxidation of a related series of primary, secondary, and tertiary amines and other nitrogen- and sulfur-containing organic compounds over a UV-illuminated film of TiO2 has been studied. The compounds were as follows: n-pentylamine, piperidine, pyridine, phenylalanine, desipramine, thioridazine, penicillamine, isosorbide dinitrate, 4-nitrocatechol, 2,4-dinitrophenol, cyclophosphamide, 5-fluorouracil, atrazine, ethylenediaminetetracetic acid, and tetrabutylammonium phosphate. Both ammonium and nitrate ions were formed. The relative concentration of the two ions depended on the nature of the nitrogen in a compound, but was also influenced by the illumination time and concentration of the solute. It was found that for n-pentylamine, piperidine and pyridine, the rate of formation of ammonium ions was n-pentylamine >> pyridine > piperidine. The order of rates of nitrate formation was pyridine = piperidine >> pentylamine. For n-pentylamine the rate of formation of ammonium ions was approximately 100 times that of nitrate.