Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Species active in the selective catalytic reduction of no with iso-butane on iron-exchanged ZSM-5 zeolites

Full text
Author(s):
M. S. Batista [1] ; M. Wallau [2] ; E. A. Urquieta-González [3]
Total Authors: 3
Affiliation:
[1] Universidade Federal de São Carlos. Departamento de Engenharia Química - Brasil
[2] Universidade Federal de São Carlos. Departamento de Engenharia Química - Brasil
[3] Universidade Federal de São Carlos. Departamento de Engenharia Química - Brasil
Total Affiliations: 3
Document type: Journal article
Source: Brazilian Journal of Chemical Engineering; v. 22, n. 3, p. 341-351, 2005-09-00.
Abstract

Fe-ZSM-5 catalysts were prepared by ion exchange in aqueous medium or in the solid state and tested in the catalytic reduction of NO with iso-butane. X-ray powder diffraction (XRD), atomic absorption spectroscopy (AAS), electron paramagnetic resonance spectroscopy (EPR), X-ray absorption spectroscopy (XANES, EXAFS), temperature-programmed reduction by H2 (H2-TPR) and Mössbauer spectroscopy (MÖS-S) were used for sample characterisation. Irrespective of the method used in catalyst preparation, EPR, XANES and MÖS-S showed Fe atoms in the oxidation state of 3+. MÖS-S and H2-TPR data on Fe-ZSM-5 prepared by ion exchange in the solid state allowed quantification of a lower hematite (Fe2O3) concentration and a higher proportion of Fe cations than samples prepared in an aqueous medium. In all the catalysts studied these Fe cations were the active sites in the reduction of NO to N2 and in the oxidation of iso-butane. It is further suggested that coordination of Fe species is another important aspect to be considered in their behaviour. (AU)