Influence of L-type activated carbons on photocatalytic activity of TiO2 in 4-chlorophenol photodegradation

The main objective of this work is to study the influence of inorganic compounds employed in the synthesis of L-type activated carbons on photocatalytic activity of TiO2 in 4-chlorophenol photodegradation. Different activated carbons were prepared from Tabebuia pentaphyla wood impregnated with ZnCl2 H3PO4 and KOH. Activation was performed under N-2 flow at 450 degrees C by I h. Results clearly indicate differences in the photoactivity of TiO2 which depends of physicochemical properties of activated carbons that are influenced by the concentration of the chemical substance. Kinetic results of 4-chlorophenol photodegradation show a synergistic effect between both solids and in certain cases the inhibition of TiO2 photoactivity. These effects have been attributed to differences in texture, topology and principally to the surface chemistry of activated carbons. Scanning electron microscopy has shown a massive aggregation of TiO2 nanoparticles on activated carbons with very acid or basic surface pH. In conclusion, the control of synthesis parameters of L-type activated carbons introduces an important enhancement in Titania's photoactivity for 4-chlorophenol photodegradation when both solids work in conjunction. (c) 2007 Elsevier B.V. All rights reserved.