Adsorption mechanism of 1,2-dichloroethane into an organophilic zeolite mordenite: A combined diffractometric and gas chromatographic study

We investigated the 1,2-dichloroethane (DCE) adsorption process into an organophilic zeolite mordenite. A combined diffractometric, thermogravimetric and gas chromatographic approach enabled to obtain clear evidence of DCE adsorption in mordenite channels as well as to pinpoint the exact location of the organic species found in the structure. Rietveld refinement revealed the incorporation of 2.5 DCE molecules and approximately 4 water molecules within the mordenite channel system, in very good agreement with the weight loss given by TG analysis and the saturation capacity determined by the adsorption isotherm. This relevant incorporation of DCE molecules caused a remarkable increase in the dimension of the 12-ring, when compared to the parent zeolite. The distances between the oxygen atoms of the water molecules from the chlorine atoms of the organic molecule (W-Cl1 = 2.34 angstrom, W-Cl2 = 2.53 angstrom) suggest that different DCE molecules could be connected by means of hydrogen bonds through water, to form a DCE and water molecule complex. The isotherm adsorption model for organic compounds from an aqueous dilute solution was selected based on the results of the structural investigation. (C) 2011 Elsevier Inc. All rights reserved.