Preparation of novel chabazite (CHA)-type zeolite layer on porous α-Al2O3 tube using template-free solution

Dehydration is an important process in chemical industries. Zeolite membranes show excellent dehydration performance as compared to other polymeric membranes. A polycrystalline chabazite (CHA) type zeolite layer with a Si/Al ratio of 3.2 was successfully formed on a porous substrate by the secondary growth of seed particles in a solution containing strontium. Furthermore, the dehydration performance of the membrane was determined by pervaporation for ethanol solutions. For a 90 wt% ethanol solution at 348 K, the overall permeation flux and separation factor of the membrane were found to be 4.14 kg m−2 h−1 and 39,500, respectively. The CHA-type zeolite membrane could remove water selectively in the solution around pH 2 for 10 h. These results suggest that the CHA-type zeolite membrane can selectively remove water from many kinds of organic solvents.