Separation of gas and organic/water mixtures by MFI type zeolite membranes synthesized in a flow system

MFI type zeolite membranes were synthesized in a recirculating flow system at 95 degrees C where the synthesis solution was flown over the tubular alpha-alumina supports. The performance of the membranes for the separation of binary gas mixtures and alcohol/water liquid mixtures was investigated. A membrane synthesized by two consecutive synthesis steps had a separation selectivity of 15 and 11 for equimolar mixtures of n-C4H10/CH4 and n-C4H10/N-2 at 200 degrees C, respectively. The membrane selectively permeated large nC(4)H(10) over small CH4 and N-2, suggesting that the separation is essentially adsorption-based and the membrane has few nonselective intercrystalline pores. The selectivities in the pervaporation separation of 5% ethanol/95% water mixture were 43 and 23 with permeate fluxes of 0.2 and 1.9 kg/m(2) h at 25 and 85 degrees C, respectively. The separation performance of membranes showed that MFI type membranes prepared in a recirculating flow system can be used both in the separation of gas and liquid mixtures. (C) 2009 Elsevier Inc. All rights reserved.