PHENOL DEGRADATION AND PHOTODEGRADATION USING O_3/UV BY Fe_2O_3 SUPPORTED ON Al_2O_3 AND TiO_2 PREPARED BY SOL-GEL METHOD

摘要

Different series of iron supported catalysts containing 10wt.% of iron, as oxide, on TiO_2 and Al_2O_3 have been prepared by the sol gel method and the traditional method based on the impregnation of the support with the metal precursor on commercial and sol-gel supports. The calcined solids were characterised by evaluating the specific surface area and porosity by nitrogen adsorption at 77 K, TPR, TPD of ammonia, X-ray diffraction, evaluation of band gap and isolelectric point by electrophoretic migration. Fe~(3+) ions in two situations were found, highly dispersed in which Fe~(3+) ions were placed in the network of the support and large Fe_2O_3 crystals were located on the surface catalysts. The catalytic activity of the prepared catalysts was measured in a batch reactor using ozone/UV as oxidizing agent. The catalysts displayed significant differences in initial reaction rate being the iron titania systems more active, specially when a higher extent of surface iron oxide species is present. After two hours on stream the conversion levels are similar in all the studied systems.