SYNTHESIS, CHARACTERIZATION AND SEPARATION PROPERTIES OF A COMPOSITE MORDENITE ZSM-5/CHABAZITE HYDROPHILIC MEMBRANE/

Composite mordenite/ZSM5/chabazite membranes were prepared on a alumin a tubular supports by in situ liquid phase hydrothermal synthesis. The membranes obtained were approximately 10 mu m thick and were characte rized by XRD, SEM and EPMA, as well as permeation of single gases (N-2 and it-butane). The membranes were then used to separate ternary mixt ures, containing water, alcohol (methanol, ethanol or propanol), and a permanent gas (O-2) Wafer permeated faster because of the hydrophilic character of the composite membrane, with water/propanol selectivitie s as high as 149. The influence of operating conditions (temperature, pressure and feed composition) on the separation performance was analy zed. Also, the behavior of this composite zeolite membrane was compare d with that of pure silicalite and ZSM5 membranes, and the differences observed are discussed in terms of relative organophilicity/hydrophil icity of the zeolites involved. (C) 1998 Elsevier Science B.V, All rig hts reserved.