New Studies about the Modified Mordenites

Mordenite is one of the rarer, but still somehow more widespread, members of the zeolite group of minerals. It has an orthorhombic unit cell of topological spacegroup symmetry Cmcm (a = 18.13; b = 20.5; c = 7.52 Å) with chemical formula: (Ca, Na2, K2)Al2Si10O24⋅7H2O (hydrated calcium sodium potassium aluminum silicate). The structure of mordenite can be described as composed of edge-sharing fivemembered rings of tetrahedra, forming chains along c-axis. Natural mordenite occurs in rather large quantities in some altered vitreous tuffs. It has a characteristic fibrous habit and if finely crystalline it may be added to the group of asbestti formous minerals causing lung diseas. The aim of this work is to obtain some modified mordenites, by modifying the SiO2:Na2O molar ratio and the stirring time. We have synthesized five mordenites using SiO2:Na2O molar ratio between 2–10 and the stirring time between 2 and 4 hours. For all the samples the porous volume, the relative density, the absorptive properties and the X-ray diffraction were determined. For the porous volume, we can observe that the smallest value was to the first mordenite (11.4 cm/g) and the highest value for the five’s mordenite (14.03 cm /g). The increasing of the porous volume determines an increasing of the density values and at the same time an increasing of the absorptive properties. X-ray data were performed at room temperature with a 1400 Philips PW difractometer, with Cu anticathode and Ni filtered.