Effect of seed precursor on organic structure-directing agent free synthesis of SSZ-13 membrane and its dehydration performance

Pure and compact zeolite SSZ-13 membrane with excellent dehydration performance was obtained with organic structure-directing agent (OSDA) free synthesis method. The seed precursor on the support affected the phase, morphology and compactness of the obtained membranes. Without the usage of the seed, GIS membrane with notable cracks were formed. Compared to the seed of H-SSZ-13, the crystallization rate of SSZ-13 crystal was faster with the NH4-SSZ-13 seed. And the crystallinity of SSZ-13 crystal prepared with NH4-SSZ-13 seed was obviously higher than that prepared with H-SSZ-13. In addition, the pure zeolite SSZ-13 can be obtained with NH4-SSZ-13 seed, while GIS impurities and SSZ-13 co-existed in the product prepared with H-SSZ-13 seed, indicating that NH4-SSZ-13 seed showed higher inductive effect than H-SSZ-13 seed on the formation of SSZ-13 crystal. Thus, pure and compact SSZ-13 membrane can be synthesized with NH4-SSZ-13 seed. The characterization results showed that the SSZ-13 membrane was obtained via dissolution-recrystallization route. Furthermore, the synthesis parameters of zeolite SSZ-13 membrane by OSDA free method were optimized systematically. The results revealed that synthesis temperature, time and the synthesis gel component would affect the morphology, phase and compactness of the obtained membrane. The SSZ-13 membrane with the optimal conditions showed good reproducibility and a relatively high pervaporation dehydration performance, the average water in permeate was 99.9%, and the average water flux was 1.82 kg/m2·h, implying that pure zeolite SSZ-13 membrane, which was obtained by OSDA free method with optimum synthesis parameters, showed a potential application value towards pervaporation dehydration process.