Combustion of trichloroethylene and dichloromethane over protonic zeolites: Influence of adsorption properties on the catalytic performance Lorena Intriago, Eva Dı ´az, Salvador Ordo ´n ˜ez * , Aurelio Vega Department of Chemical Engineering and Environmental Technology, University of Oviedo, Julia ´ n Claverı ´a s/n, 33006 Oviedo, Spain Received 15 August 2005; received in revised form 17 November 2005; accepted 23 November 2005 Available online 9 January 2006 Abstract The deep oxidation of dichloromethane (DCM) and trichloroethylene (TCE) over protonic zeolites (HA, HX, HY and H-ZSM-5) was studied in this work. Experiments were performed in dry air in the range 50–650 °C in a pulsed microreactor. Catalytic activity was cor- related with the capacity of adsorption of DCM and TCE as well as the strength and specificity of these interactions, which parameters were determined by inverse gas chromatography (IGC). DCM is oxidized at lower temperatures than TCE, and at the same time, the interaction of this compound over the catalysts is also stronger than that of TCE. The increase of the TCE conversion in presence of the catalysts was very low, whereas these materials (specially the HY and H-ZSM-5 zeolites) have important catalytic activity for DCM oxidation. The best performance of these zeolites has been attributed to the higher density of strong acid sites, which act as active sites both in the adsorption of hydrocarbon and catalytic activation of hydrocarbon halides. The product distribution is also discussed in this work. Ó 2005 Elsevier Inc. All rights reserved. Keywords: Catalytic oxidation; Trichloroethylene; Dichloromethane; H-type zeolites 1. Introduction Chlorinated volatile organic compounds (ClVOCs) have been produced commercially and used for many purposes in different industries, including the manufacture of herbi- cides, plastics, and solvents. Trichloroethylene (TCE) and dichloromethane (DCM) constitute a significant fraction of these ClVOCs, whose uses outside the chemical industry include degreasing agents in the automotive and aerospace industries, solvent for dry-cleaning in the garment indus- tries, and solvent clearing in the electronic industries. How- ever, such compounds present important hazards for the environment and the human health. So, in addition to be related to the formation of chemical smog, they tend to accumulate in biological systems and may develop toxic properties in organisms. Removal of chlorinated hydrocar- bons from flue-gases by catalytic combustion is recently receiving increasing attention because their growing impor- tance in pollution control. Among the various disposal methods applicable, low temperature catalytic destruction appears to be one of the most promising and effective technologies for the abatement of these compounds. The desired reactions are the complete oxidation of the chlori- nated compounds to produce CO 2 ,H 2 O and HCl. Alumina-supported noble metal catalysts have been intensively studied and successfully used for the deep oxi- dation of these compounds [1], but their high cost and limited availability encourage their replacement by other active compounds. Zeolites have gained interest as poten- tial active catalysts for the oxidation of hydrocarbons [2,3] because of their pore structures, acidic properties, good thermal stability and ion exchange properties. They have traditionally received great interest because of their optimum performances as solid acid catalysts in refining 1387-1811/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.micromeso.2005.11.043 * Corresponding author. Tel.: +34 985 103437; fax: +34 985 103434. E-mail address: sordonez@uniovi.es (S. Ordo ´n ˜ ez). www.elsevier.com/locate/micromeso Microporous and Mesoporous Materials 91 (2006) 161–169