PEI/MCM-48 Composite Membranes for Carbon Dioxide Separation

摘要

The cubic MCM-48 membranes were synthesized on alpah-alumina supports containing 0.2 mu m pores (A16 alumina) by solution growth method under hydrothermal conditions. MCM-48 was observed inside the pores of the alumina support and as a continuous membrane layer on the support surface. A viscous flow contribution was observed for N_2 transport through the MCM-48 membranes prepared on A16 alumina supports when the surfactant was removed by calcination. Calcination to remove the surfactant results in a contraction of the MCM-48 unit cell size and generation of large gaps between the MCM-48 particles which contributes to viscous gas flow. Superior quality membranes were prepared on the A16 supports when the surfactant was removed by Soxhlet extraction using an EtOH/HCl mixture. No dependence of N_2 permeance on pressure was observed for these membranes indicating Knudsen diffusion regime for the N2 transport. Polymeric amino groups were successfully attached to the pore surface of the MCM-48 membranes which resulted in the N_2/CO_2 selectivity. Further studies are currently underway to establish the molecular mechanism of the observed N_2/CO_2 selectivity.