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Photodegradation of chloroform and urea using Ag-loaded titanium dioxide as catalyst

1991; Elsevier BV; Volume: 25; Issue: 7 Linguagem: Inglês

10.1016/0043-1354(91)90162-j

1879-2448

Márcia Matiko Kondo, Wilson F. Jardim,

Advanced Nanomaterials in Catalysis

The photodegradation of chloroform and of urea in aqueous solutions was investigated under near-u.v. and visible radiation using the anatase form of TiO2 as catalyst. It has been shown that the catalytic activity of the TiO2 can be increased by loading silver, in a proportion of 1% (w/w), onto the oxide surface. In a solution containing 200 mg I−1 of chloroform, the photodegradation achieved using the Ag-loaded oxide was 44% compared to the 35% obtained using the pure (unloaded) oxide. This photoactivity was further enhanced in a solution containing 25 mg 1−1 of chloroform. Upon reuse, a decrease in the photocatalytic activity was observed in both oxides, but to a lesser extent in the Ag-loaded TiO2. An increase in the photocatalytic activity of the silver-loaded oxide was also noted in the degradation of a 100 mg 1−1 aqueous solution of urea. After 12 min of irradiation, the Ag-loaded oxide destroyed 83% of this compound, compared to a 16% efficiency obtained for the pure form of anatase. After 6 h of irradiation, 0.5 mg 1−1 of silver ions were detected in the Ag-loaded TiO2 suspension.