Cobalt-exchanged Mordenite onto a cordierite honeycomb for the SCR of NO

GLORIA GONZÁLEZ; MARIANO ERCOLI; JUAN M. ZAMARO; CLAUDIA QUINCOCES; EDUARDO E. MIRÓ

Village Rio das Pedras, Rio de Janeiro, Brasil

Congreso; 2nd Mercosur Congress on Chemical Engineering. 4th Mercosur Congress on Process Systems Engineering (EMPROMER); 2005

UFRJ (Brasil)

Structured catalysts were prepared by deposition of Cobalt-exchanged mordenite films on the walls of cordierite monolith channels either by washcoating or by hydrothermal synthesis. The aim of this work is to analyze different deposition techniques and their influence on the catalytic activity, which is compared with that of the powder form of the zeolite. The hydrothermal synthesis was performed in situ in a pressured autoclave reactor varying the reaction conditions (time, stirring degree). This technique consists in the crystallization of zeolite (mordenite) on the cordierite employed as a substrate. In order to analyze the stirring effect, some of the samples were synthesized by stirring while others were treated in a stagnant medium. The influence of time on reaction was estimated by sampling at regular time intervals. Deposition by impregnation (washcoating) was also performed by immersing the monolith into a suspension (20-40 wt. %) with Co-exchanged mordenite. A binder (colloidal SiO2) has been added to improve the adherence of the solid film. The washcoating was performed under different conditions (suspension concentration, incorporation of agglutinants or number of immersions) to obtain a zeolite coating active and selective as catalyst for the nitric oxide selective reduction with hydrocarbons. The samples obtained by either method were characterized by scanning microscopy, TPR, XRD and catalytic activity for the SCR of NOx with propane.