Preparation and properties of a new composite photocatalyst based on nanosized titanium dioxide

The use of photocatalysts supported on adsorbents is receiving substantial attention. Supporting TiO₂ with zeolites is found to be one of the best solutions to increase the efficiency of TiO₂-based photocatalysts. This work was focused on simple preparation of a TiO₂/Na-ZSM-5 composite catalyst by the solid state dispersion (SSD) method and its modification with an organic photosensitizer — polythiophene (PT). Using the XRD diffractometry, structure of the new composite catalyst was proved. Beside this composite catalyst, mechanical mixtures of TiO₂-based catalysts with Na-ZSM-5 zeolite were prepared. The efficiency of all five available photocatalysts (TiO₂, TiO₂-PT, mechanical mixture of TiO₂ + Na-ZSM-5, mechanical mixture of TiO₂-PT + Na-ZSM-5, and the modified SSD-PT composite) on photodegradation of 4-chlorophenol was compared. By measuring the formation of chloride ions and decreasing the 4-chlorophenol concentration at two different initial concentrations of 4-chlorophenol in the basic aqueous solution, the photoefficiency and adsorption properties of our photocatalysts were determined. Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May 2008.