Photocatalytic Activity of Titanium Dioxide Immobilized in Polyacrylamide Hydrogels with Different Degrees of Crosslinking

摘要

Composite filamentary hydrogels based on cross-linked polyacrylamide, filled with TiO2 particles, were synthesized. The degree of crosslinking of the hydrogel matrix was set by the molar ratio of the cross-linking agent and monomer: 1 : 50, 1 : 100, 1 : 200, or 1 : 300. The diffusion of Methyl Orange dye in the polymer matrix as a function of the degree of crosslinking was studied by spectrophotometry, and the diffusion coefficient was calculated: 1.4 x 10(-6), 1.8 x 10(-6), 3.4 x 10(-6), and 4.8 x 10(-6) cm(2) s(-1), respectively. The photocatalytic activity of the composite hydrogels toward UV-induced degradation of a model dye, Methyl Orange, was studied. The effective rate constants of the photocatalytic degradation of the dye under the action of polyacrylamide/TiO2 composite hydrogels and aqueous TiO2 suspensions were determined. The presence of the hydrogel polymer matrix reduces the photocatalytic activity of TiO2 particles compared to the aqueous suspension containing the same amount of the particles. The photocatalytic activity of both aqueous TiO2 suspension and polyacrylamide/TiO2 composite hydrogel linearly depends on the total amount of TiO2 particles in the system.