The characteristics of a copper-exchanged natural zeolite for NO reduction by NH3 and C3H6

Abstract

The catalytic performance of the natural zeolite mined from Youngil, Korea was investigated when two types of reductant such as NH3 and hydrocarbons were employed for the reduction of NO. The determination of the structure of the natural zeolite has also been made to identify the type of zeolite and to examine its use as a catalytic material for NO removal reaction. The elementary analysis and electron probe microanalysis of the zeolite revealed that it typically consisted of an aluminosilicate. Although it mainly contains mordenite-type zeolite, heulandite was also included as well as the phases of quartz and feldspar as an impurity in the zeolite. This result could be also confirmed by the X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses. It should be noted that the acid treatment of the natural zeolite for its use as a catalytic material is essential for the high performance of NO reduction by selective catalytic reduction (SCR) technology. Copper ion-exchanged natural zeolite catalyst (CuNZA) exhibits a competitive NO reducing activity for the reduction of NO by NH3 as well as hydrocarbons. It can be regarded as a promising catalytic system by NH3 and hydrocarbons for the removal of NOx from stationary and mobile sources. (C) 1998 Elsevier Science B.V. All rights reserved.