Preparation and Pervaporation Properties of X- and Y-Type Zeolite Membranes

Abstract

NaX and NaY zeolite membranes were prepared hydrothermally on the surface of a porous, cylindrical mullite support and were characterized by X-ray diffraction and scanning electron microscopy. The surface of a membrane prepared at 100°C for 5 hours was completely covered with randomly oriented, intergrown NaX or NaY zeolite crystals and the thickness of the membrane was about 20-30 μm. NaX and NaY zeolite membranes preferentially permeated water in pervaporation experiments of water/alcohol mixtures. The membrane was also highly alcohol-selective in pervaporation of alcohol/benzene, cyclohexane, or methyl tert-butyl ether (MTBE). The high selectivity of the NaY zeolite membrane can be attributed to the selective sorption of methanol into the membrane. A pervaporation process using a NaY zeolite membrane may be an alternative method for the industrial purification of MTBE.Pervaporation has gained some acceptance in the chemical industry as an effective process for the separation of azeotropic mixtures {1,2). For example, pervaporation has been applied to the dehydration of organic liquids (ethanol, /-propanol, ethylene glycol etc.). Application of pervaporation for the separation of organic liquid mixtures, such as aliphatic-aromatic hydrocarbons or alcohols-ethers, however, is still very limited because of the low selectivity of most polymer membranes. On the other hand, membranes made from inorganic materials are generally superior to those made from polymeric materials in thermal and mechanical stability as well as chemical resistance. Among inorganic materials, zeolites are promising candidate materials for high-performance pervaporation membranes because of the unique characteristics of zeolite crystals such as molecular sieving, ion exchange, selective adsorption, and catalytic properties. Recently, we reported on the excellent 330

Silicalite Membrane Preparation, Characterization, and Separation Performance

“…The former seeding method was first used for synthesis of zeolite A membranes by our group, 11 which has been identified as an effective and reproducible seeding method. [12][13][14][15]24 A clear solution for the synthesis of silicalite membranes was prepared by mixing and stirring tetraethyl orthosilicate (TEOS of Aldrich), TPAOH, and deionized water at room temperature for 1 h. The resultant molar composition is 0.17/1/120 SiO 2 /TPAOH/H 2 O. The seeded support was vertically immersed in the synthesis solution.…”

Polymeric Nanocomposite Membranes for Next Generation Pervaporation Process: Strategies, Challenges and Future Prospects

“…Among various inorganic NPs, zeolite has emerged as one of the best options for the betterment of both selectivity and permeability due to the prevalent unique molecular sieving property and selective adsorption [ 164 , 334 ]. Recently, zeolite filled membranes have exhibited reasonable flux and separation performances than the traditionally used polymeric membranes [ 335 , 336 ]. However, the fabrication of zeolite membranes is expensive and usually brittle.…”

Hybrid composite membranes of sodium alginate for pervaporation dehydration of 1,4-dioxane and tetrahydrofuran

“…several hybrid composite membranes loaded with inorganic zeolite particles have been developed and used for dehydrating organics [5][6][7][8][9][10][11][12][13][14]. Separation using zeolitefilled PV membranes occurs by adsorption-desorption and molecular sieving effects due to the presence of small particles [15]. Aminabhavi et al [16][17][18][19][20][21][22] used different fillers to develop mixed matrix membranes of sodium alginate (NaAlg) for PV dehydration of organic liquids.…”