Preparation of chabazite membranes by secondary growth using zeolite-T-directed chabazite seeds

Chabazite crystals were directly prepared from template-free aluminosilicate gel with the addition of nano-sized zeolite T (∼100 nm). This new route requires only one thirtieth seeds amount for a certain product, and one twentieth synthesis time compared with the classic one by the conversion of zeolite Y crystals. A pure and dense chabazite membrane was prepared on macroporous supports by secondary growth. The membrane synthesis parameters such as seeds, supports and synthesis time on membrane formation and pervaporation performance were also studied. Eight chabazite membranes prepared on macroporous stainless-steel supports showed a high average flux of 3.4 kg m^-2 h^-1 and high average selectivity of 2100 with low deviations on the flux and selectivity for a water/ethanol (10/90 wt%) mixture at 75 C, indicating membrane synthesis using stainless-steel supports had a good reproducibility. The as-synthesized chabazite membranes also showed good hydrothermal stability under pervaporation test in a water-rich ethanol aqueous solution.