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Photocatalytic degradation of phthalic acid on TiO2 nanoparticles

Department of Chemistry, National Research Council of Argentina, University of Mar del Plata, P.O. Box 422, 7600 Mar del Plata, Argentina
Applied Catalysis A General (Impact Factor: 3.41). 06/2001; 208:419-426. DOI: 10.1016/S0926-860X(00)00727-4

ABSTRACT The photocatalytic oxidation of phthalic acid was studied in aerated sols of TiO2 nanoparticles under monochromatic irradiation at pH=4.25. We report initial quantum efficiencies for phthalate degradation, ΦPHT0, as a function of phthalate concentration and quantitative yields of the primary products. Formation rates of the hydroxyl radical adduct (DMPO-OH) from the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were determined at various initial concentrations of phthalate. Kinetic analysis of the spin-trapping experiments indicates that phthalate is oxidized by a dual hole-radical mechanism. The effect of added phosphate on phthalate photocatalytic degradation is examined in detail. Dark-adsorption of phthalate on TiO2 particles is significantly inhibited by the presence of phosphate, however, ΦPHT0 is almost independent of phosphate concentration.

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