Immobilization of TiO2 on perlite granules for photocatalytic degradation of phenol

The photocatalytic degradiation of phenol by nanoTiO(2) particles coated on perlite as a new composite nano-catalyst was investigated. Titanium dioxide (Degussa P-25) was immobilized on three different supports (perlite granules, glass plates and steel fiber) by a very simple and inexpensive method. Perlite granules have a porosity of more than 95%, which allows them to stay afloat on water surface. This gives the medium a unique characteristic from the processing point of view, which enables it to get wetted with the polluted solution without requiring any pumping and simultaneously be exposed to the radiation source when coated with the photocatalyst. The photocatalytic activity of prepared catalysts was tested in appropriate batch reactors. HPLC analyses was used for measuring the concentration of components. XRD and SEM analyses was carried out for characterization including anataze-rotile phase ratio, crystal size and morphology of prepared catalysts. The XRD results did not reveal any significant changes in the structure of P-25 as a consequence of the applied immobilization process. Also, well and uniform coating of TiO2 on supports were confirmed by SEM method. The obtained results of the photocatalytic treatment experiments of water synthetically polluted with phenol showed a fairly good performance for the three immobilized catalysts. The rate of phenol degradation was positively affected by UV light intensity, according to different intensity of UV lamps, the kinetics of photocatalytic reaction follows a pseudo-first-order model. Also control experiments confirmed that the effects of adsorption and degradation of phenol onto the TiO2/perlite catalysts in the dark conditions were negligible. (c) 2007 Elsevier B.V. All rights reserved.