Design of metal loaded zeolites as dual functional adsorbent/catalyst system for VOC control

Abstract

Metal loaded zeolite HY was proposed as dual functional adsorbent/catalyst media for the control of low concentration VOC streams, which has both high adsorption capacity and catalytic activity. To design a good dual functional system, both adsorption and catalytic activity test were carried out. Hydrophobic HY zeolite showed a high adsorption capacity comparable to activated carbon and better desorption features for the cyclic operation. Metal addition endowed HY zeolite adsorbent with catalytic activity for VOC oxidation, which should be applicable to the dual functional adsorption/catalytic oxidation system. The temperature programmed surface reaction (TPSR) of toluene and methylethylketone suggested the silver as the best candidate among the tested transition metals. Temperature programmed reductions (TPR) and O-2-temperature programmed desorption (O-2-TPD) on Ag/HY catalysts were carried out to explain the nature of active centre of Ag catalyst for the toluene oxidation. Silver oxide species or partially oxidized metallic silver on to the surface of metallic silver phase was proposed as an active redox site during the oxidation reaction.