Catalytic and photocatalytic ozonation of phenol on MnO2 supported catalysts

Different series of manganese-supported catalysts containing 10 wt.% of manganese, as oxide, on TiO2 have been prepared by the sol-gel method and by the traditional method based on the impregnation of the support with the metal precursor on commercial and sol-gel supports. The samples were characterized by measuring the specific area (S-BET), temperature-programmed desorption (TPD), Fourier transform infrared (FTIR) spectroscopy, temperature-programmed reduction (TPR), electrophoretic migration (IP) and X-ray diffraction (XRD). The catalytic and photocatalytic activity was measured in a batch reactor using ozone as the oxidizing agent. The catalytic behavior, expressed as constant rate, in absence of irradiation did not show significant changes for the manganese-supported catalysts. The only exception was the cogelated Mn/TiO2 catalyst, which showed higher degradation activity, the main product being benzoquinone. On the other hand, all the irradiated systems showed an increase in the phenol degradation, being CO2 and small organic acids the final product. (C) 2002 Elsevier Science B.V. All rights reserved.