Catalytic combustion of polycyclic aromatic hydrocarbons (PAHs) over zeolite type catalysts: Effect of water and PAHs concentration

• Published in: Applied catalysis. B, Environmental Environmental, 2009-08, Vol.90 (3-4), p.489-496
• Main Authors: Marie-Rose, S.C., Belin, T., Mijoin, J., Fiani, E., Taralunga, M., Nicol, F., Chaucherie, X., Magnoux, P.
• Format: Article
• Language: English
• Subjects: Byproducts; Carbon dioxide; Catalysis; Catalysts; Chemistry; Exact sciences and technology; Faujasite; General and physical chemistry; Ion-exchange; Methylnaphtalene; Moisture content; Platinum; Polyallylamine hydrochloride; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; USHY; Water cluster; Zeolites; Zeolites: preparations and properties
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2009.03.035

The catalytic combustion of 1-methylnaphthalene (1-MN), a PAH representative molecule, was carried out over USHY and 0.8%PtUSHY catalysts in presence of steam. These catalysts are able to transform low concentration of 1-MN into carbon dioxide at 300°C over USHY catalyst and at 200°C over PtUSHY, without by-products formation. The presence of platinum on the USHY increases the catalytic activity, hence the reaction rate. The influence of platinum content showed that 0.5% of platinum deposited on the zeolite was sufficient to oxidize 900ppm of 1-MN at 300°C. The influence of water content in the feed was investigated and several assumptions were put forth to explain our results. The carbon dioxide yield decreases in the 0–12% range of relative humidity (RH). When RH increases up to 12% the carbon dioxide yield increases. Over USHY catalyst and for low water content (RH12%), water cluster formation via H2O dimer (ion-pair complex form) is proposed on both catalysts. This form of H2O dimer (ion-pair complex) could generate an acidity, which facilitates the formation of oxygenated compounds easily degradable into carbon dioxide.