Applied Catalysis B: Environmental 24 (2000) 233–242 Evaluation of H-type zeolites in the destructive oxidation of chlorinated volatile organic compounds J.R. González-Velasco ∗ , R. López-Fonseca, A. Aranzabal, J.I. Gutiérrez-Ortiz, P. Steltenpohl 1 Department of Chemical Engineering, Faculty of Sciences, Universidad del Pa´ ıs Vasco/EHU, P.O. Box 644, E-48080, Bilbao, Spain Received 15 May 1999; received in revised form 11 July 1999; accepted 3 September 1999 Abstract The deep oxidation of 1,2-dichloroethane (DCE) and trichloroethylene (TCE) over H-type zeolites (H-Y and H-ZSM-5) was evaluated. Experiments were performed at conditions of lean hydrocarbon concentration (around 1000 ppmv) in dry air, between 200 and 550 ◦ C in a conventional fixed-bed reactor. H-ZSM-5 zeolite resulted more active than H-Y zeolite in the decomposition of both chlorinated volatile organic compounds. It was established that Brønsted acidity plays an important role in controlling the catalytic behaviour of the H-type zeolites. DCE was completely decomposed at 400 ◦ C, whereas TCE required higher temperatures (550 ◦ C). Vinyl chloride was identified as an intermediate in the DCE oxidation in the range of 250–400 ◦ C. When vinyl chloride is destroyed at higher temperatures, both zeolite catalysts show a high selectivity (>90%) towards HCl formation. Trace amounts of tetrachloroethylene were detected in the TCE oxidation, which peaked at 500 ◦ C. CO was promoted in quantity in the destruction of both DCE and TCE reflecting the difficulty of carbon monoxide oxidation over H-type zeolites. ©2000 Elsevier Science B.V. All rights reserved. Keywords: Catalytic oxidation; Chlorinated volatile organic compounds; H-type zeolites; H-Y; H-ZSM-5; 1,2-Dichloroethane; Trichloroethylene; Brønsted acidity; Selectivity 1. Introduction Chlorinated volatile organic compounds (CVOCs) are found in many industrial waste streams. Sub- stantial quantities of 1,2-dichloroethane (DCE) are generated in vinyl chloride production plants [1] and trichloroethylene is widely used in dry cleaning and degreasing processes. Both compounds are present in ∗ Corresponding author. Tel.: +34-94-6012-681; fax: +34-94-4648-500. E-mail address: iqpgovej@lg.ehu.es (J.R. Gonz´ alez-Velasco). 1 On leave from Department of Chemical and Biochemical En- gineering, Slovak University of Technology, 812 37 Bratislava, Slovak Republic. air stripping and soil venting remediation off-gases [2]. These chemical compounds are well known to be toxic to human beings and to be involved in the depletion of the ozone layer in the stratosphere. In recent years the emission of chlorinated com- pounds to the atmosphere has been under scrutiny leading to the introduction of legislation (US 1990 Clean Air Act) imposing strict controls on permitted levels. These stringent regulations have stimulated the development of technology to remove efficiently such hazardous compounds from waste streams. Traditionally conventional technology for VOCs de- struction, particularly chlorocarbons, has been ther- mal combustion, which requires operating tempera- tures ranging from 800 to 1000 ◦ C and can lead to 0926-3373/00/$ – see front matter ©2000 Elsevier Science B.V. All rights reserved. PII:S0926-3373(99)00105-8