Preparation of Nanopore Hydroxysodalite Zeolite Membranes by Dry Gel Method

Abstract

Hydroxysodalite (HS) Zeolite membrane was prepared onto seeded mullite supports using a new crystallization method called Dry Gel Conversion Technique. Molar composition of the starting gel of HS zeolite membrane was SiO2/Al2O3=1.0, Na2O/Al2O3=65, and H2O/Al2O3=1000. X-ray diffraction (XRD) patterns of the membranes exhibited peaks corresponding to the support and the zeolite. The crystal species were characterized by XRD and morphology of the supports subjected to crystallization was characterized by Scanning electron microscopy (SEM). Separation performance of HS zeolite membranes was studied for water-Ethanol mixtures using pervaporation (PV). The membranes showed good selectivity towards water in the water-ethanol mixtures. Water permeates faster because of its preferential adsorption into the nano-pores of the hydrophilic zeolite membrane. In PV of water-ethanol mixtures, the membrane exhibits a hydrophilic behavior, with a high selectivity towards water and a good flux. The best flux and separation factor of the membranes were 2.05 kg/m.h and 10000, respectively. In addition, these membranes used for hydrogen separation from CH4 and it showed high selectivity and permeability ratio to zeolite membrane preparated by conventional method.