INVESTIGATION OF AQUEOUS ADSORPTION-DESORPTION OF PESTICIDE ON SIO2 GEL IN PHOTOCATALYSIS BY SILICA-SUPPORTED TITANIUM-DIOXIDE

Commercial titanium dioxide powder is a powerfull photocatalyst but it s small grain size (30 mm) gives filtration difficulties. Titanium dio xide (TiO2) has been supported in silicon dioxide prepared by sol-gel route. The catalytic mass obtained is photo-efficient in the carbetami de degradation. However, to facilitate the correct TiO2 distribution i n the catalytic support, the mass of the silica gel must be higher tha n that of the TiO2 catalyst. The silicon dioxide gel appears as a very good adsorbant for carbetamide (specific surface area higher than 600 m(2)/g). Using this property in the water depollution field the catal ytic mass can be employed as an adsorbant-catalyst and then, can be re generated by the photocatalytic process [1].