Adsorption and photocatalytic properties of V-N-TiO₂/attapulgite and V-N-TiO₂/glass beads composites

The adsorption characteristics and photocatalytic properties of self-developed V-N-TiO₂, V-N-TiO₂/attapulgite and V-N-TiO₂/glass beads composites were studied. The humic acid, methylene blue, and dimethylformamide were used as the target degradants. The results show that the adsorption of humic acid and methylene blue except dimethylformamide by V-N-TiO₂, V-N-TiO₂/attapulgite and V-N-TiO₂/glass beads composites, attapulgite, glass beads conforms to the Langmuir isotherm model. The loading form of V-N-TiO₂/attapulgite and V-N-TiO₂/glass beads composites has the greatest influence on its adsorption performance. All photocatalytic reactions of humic acid and methylene blue by V-N-TiO₂, V-N-TiO₂/attapulgite and V-N-TiO₂/glass beads composites are consistent with the first-order kinetic equation. The photocatalytic property of V-N-TiO₂/attapulgite and V-N-TiO₂/glass beads composites is related to the adsorption equilibrium constant K_a and the photocatalytic surface reaction rate constant K_r. When the composite has a large difference in the value of the adsorption equilibrium constant for different target degradation products, the greater the adsorption equilibrium constant, the greater the reaction rate constant, the faster the photocatalytic reaction proceeds. When the composite does not differ greatly in the value of the adsorption equilibrium constant for different target degradation products, the greater the photocatalytic surface reaction rate constant, the greater the reaction rate constant, and the faster the photocatalytic reaction proceeds.