PREPARATION AND PHOTOCATALYTIC APPLICATION OF DIFFERENT TiO_2 AND Zn(OH)_2/ZnO NANOPARTICLES AND HYDROPHILIC/HYDROPHOBIC LAYERED SILICATES

摘要

TiO_2 nanosol particles were prepared by acidic hydrolysis of titanium tetraisopropoxide, and the incorporation of the anatase nanoparticles was next carried out between the layer silicate sheets by heterocoagulation method. TiO_2/montmorillonite nanocomposites with high specific surface areas (a~S_(BET) = 130-284 m~2 g~(-1)) were characterized and tested as photocatalysts by mineralization of phenol. Self-assembled multilayer films from Zn(OH)_2/ZnO nanoparticles and hectorite were prepared and the optical and structural properties were investigated. Significant photodegradation of !!!-naphtol and kerosene was found in the presence of the nanofilms, in the flow photocatalytic experiments. The degradation of 2-chlorophenol was investigated by a combination of TiO_2-based photocatalysis and adsorption. The differently prepared adsorbent-photocatalyst systems were characterized by X-ray diffraction measurements. The most advantageous situation was found when the hexadecylpyridinium chloride-treated montmorillonite was used as adsorbent and Degussa P25 TiO_2 as photocatalyst, for which the highest rate of oxidation of 2-chlorophenol was observed. In this case the photocatalytically recovered adsorbent may be re-used without further regeneration.