Growth of High Quality, Thickness-Reduced Zeolite Mem-Branes Towards N2/CH4 Separation Using High-Aspect-Ratio Seeds

Greatly improved zeolite membranes were prepared by using high-aspect-ratio zeolite seeds. Slice-shaped seeds with large aspect ratio (AR) facilitated growth of thinner continuous SAPO-34 membranes with much higher quality. These membranes showed N2 permeances as high as 2.87×10-7 mol/(m2•s•Pa) at 22 oC while maintaining decent N2/CH4 selectivity (9~11.2 for equimolar mixture). On the basis of these thinner and high quality SAPO-34 membranes, fine tuning the local crystal structure by incorporating more silicon further increased N2 permeance by 1.4 times without sacrificing the N2/CH4 selectivity. We expect employment of large AR zeolite seeds might be a viable strategy to grow thin and high quality zeolite membranes. In addition, fine tuning crystal structure by changing crystal composition might be a feasible way for further improving separating performance of high quality zeolite membranes.