[Studies in Surface Science and Catalysis] Impact of Zeolites and other Porous Materials on the new Technologies at the Beginning of the New Millennium, Proceedings of the 2nd International FEZA (Federation of the European Zeolite Associations) Conference Volume 142 || Characterization of H and Cu mordenites with varying SiO2/Al2O3 ratios, by optical spectroscopy, MAS NMR of 29Si, 27Al and 1H, temperature programmed desorption and catalytic activity for nitrogen oxide reduction