Effect of Ca and K promoters on the catalytic activity of Co/zeolite Y for removing of NO2 as a pollutant gas

Zeolites have been used mainly as adsorbent, catalyst and support in the last decades. The mentioned applications are because of the unique properties of the zeolites such as high surface area, pore volume and ordered channels in these materials. Primary building units of TO4 (T = Al or Si) lead to secondary building units which from the zeolite. By increasing the ratio of Al/Si, thermal stability of the zeolite increase. Among these zeolites, the Y type has wide applications in industry as adsorbent, molecular sieve, ion exchanger and catalyst. Y zeolite is made from double six rings and super cages. This low density Y zeolite is active and stable in order to use in petrochemical industry [38]. Y zeolite which has been ion exchanged by Co+2 was utilized in desulfurization process [51]. The same catalyst was use for the conversion of ethane to acetonitrile [53]. Modification of the Y zeolite with a wide range of the cations will improve and promote its activity in many important processes. NOX is referred to NO and NO2 which is produced at high temperature. NOX is the main pollutant of the air and is very dangerous for the environment. Many attempts devoted for removing NOX such as selective none catalytic reduction (SNCR) and selective catalytic reduction (SCR). NO is thermodynamically stable because it has high activation energy (364 KJ/mol). Therefore it better use a catalyst for its degradation. NOX is produced from the vehicles and petrochemical units. Zeolites, metal oxides and perovskites are the main catalytic supports for removing the NOX. One of the most effective methods for removing the NOX is using NH3 (SCR-NH3/NOx). Because this system shows high yield of (96-99%) NOX removing. 4NH3 + 4NO + O2 4N2 + 6H2O V/TiO2 , Pt and zeolites are common catalysts for this process. In this study, Co/Y zeolite promoted by potassium and calcium to be used for NH3-SCR process.