Thin Sapo-34 Zeolite Membranes Prepared By Ball-Milled Seeds

Zeolite membranes demonstrated great separation performance for many important separation processes, however, high membrane cost is a major obstacle for its commercial application. Reducing membrane thickness is an effective way of lowering its unit cost, which requires a delicate control of nucleation and crystallization processes. Herein, the effect of seed size on the separation performance of SAPO-34 membranes was studied. Smaller seeds facilitated secondary nucleation which led to thinner membrane with higher CO2 permeance. Ball-milling of regular SAPO-34 crystals can generate ultra-small seed particles easily, which is even better than tailor-made nano SAPO-34 seeds on reducing membrane thickness. Thin SAPO-34 membrane with thickness similar to 1.4 mu m can be prepared with high reproducibility and high CO2 permeance similar to 10.2 x 10(-7) mol.m(-2).s(-1).Pa-1 and CO2-CH4 selectivity of 59 were obtained for the separation of equalmolar CO2-CH4 mixture at 4.0 MPa and room temperature.