A novel device for preparing zeolite -: A membranes under a centrifugal force field

A new system is presented for the synthesis of zeolite membranes in the lumen of tubular supports. The support is placed inside a device that rotates around its longitudinal axis during the synthesis. Centrifugal forces produced by high rotational speed drive the crystals and crystal nuclei formed in the homogeneous phase towards the support surface, promoting the formation of a more continuous and dense layer. In addition, because of its design this device works as a centrifugal pump, creating a shear flow and renewing continuously the solution in contact with the growing zeolite layer. With this system, zeolite A membranes were reproducibly prepared on top of tubular alumina supports at 100degreesC, using seeded and unseeded hydrothermal synthesis, and different gel compositions. The water/alcohol pervaporation results obtained so far gave separation factors higher than 130 at water fluxes over 2.5 kg/(h m(2)). (C) 2002 Elsevier Science B.V. All rights reserved.