Catalytic oxidation of carbon tetrachloride on metal exchanged Y-zeolite

Abstract

In this contribution we present the results of a kinetic study of the catalytic combustion of carbon tetrachloride over several catalysts of Y-zeolite exchanged with Cr, Co, Mn and Fe. The catalysts were prepared by ion exchange and characterized, before and after catalytic tests, by atomic absorption, N2 physisorption (BET surface measurement) and X-ray diffraction. The experimental results have been analyzed using both empirical, -power-law pseudo-homogenous-, and mechanistical -Langmuir-Hinshelwood-models. The catalytic results indicate the following order ofactivity: Y-Co > Y-Cr=Y-Fe > Y-Mn. According to the mechanism assumed to explain the kinetic results obtained, the oxygen molecule adsorbs over the surface Co++ species, and the carbon tetrachloride interacts with the H+ ion on the Brönsted acid site. It was also obtained that the presence of water in the feed is necessary to avoid the deactivation of the catalyst. This effect is probably due to the capacity of water to restore the Brönsted acid sites depleted during the reaction.