Abstract

A study was made of the catalytic oxidation of a model mixture of effluents from forest biomass combustion equipment, consisting principally of methane (CH 4), naphthalene (C 10H 8), carbon monoxide (CO) and oxygen-poor air (10% O 2, balance N 2), in a laboratory reactor, using MeOx/TiO 2 catalysts (Me = Fe, Cu or Mn), prepared using incipient wetness impregnation. It was observed that the addition of metal oxides to the TiO 2 increases catalytic activity in the combustion of all the contaminants present in the model effluent (CH 4, C 10H 8 and CO). The catalysts were characterised using the following techniques: SBET, XRD, DTG/DTA and TPD-NH 3; and from these it was observed that the support presented only the anatase phase in all the catalysts, despite having been subjected to temperatures in excess of 1.000 K during combustion. The highest acidity among all the solids tested, measured by TPD-NH 3, was obtained for the FeOx/TiO 2 catalysts, which were also those which showed the greatest catalytic activity. This high level of activity may be related to the formation of isolated metallic phases; i.e. hematite (Fe 2O 3), which would be the active phase in the combustion of C 10H 8 and CH 4. On the other hand, with to respect to the 5 % wt. values of Me/TiO 2 (Me: Fe, Cu y Mn) catalysts, the CuO/TiO 2 catalyst shows greater activity than Fe 2O 3/TiO 2 and MnOx/TiO 2 for the oxidation of CO, which would be related to the formation of CuO on the TiO 2 surface. The formation of mixed phases between the metals and the TiO 2 was not observed. The SBET of the most active catalyst, Fe 2O 3/TiO 2 (where Fe is 5% w/w in value), was not subject to any changes during the reaction. © 2007 Sociedad Chilena de Química.