Membrane materials and fabrication methods often need to be co-developed to meet the specific permeance and selectivity requirements of different gas separation application, which limits the adaptability of membrane technology. Here we propose a post-regulation strategy—adjusting the pore structures of a standard “primitive” membrane to meet various separation needs—that greatly simplifies membrane preparation and accelerates technological advancement. Graphene quantum dots (GQDs) are introduced as innovative building blocks: a continuous GQD membrane is constructed by tightly stacking GQDs, and then its pore structure is tuned via heat treatment and in-situ cross-linking with small amine molecules. Combining adjustable angstrom-scale pores with preferential CO2 adsorption, the resulting GQD membranes exhibit widely tunable CO2/N2 and CO2/CH4 separation performances. The CO2 permeance and separation factors surpass most reported membranes and can be tuned to exceed industrial targets for CO2 capture. By varying the heat treatment temperature, the separation scope of the membrane is further extended to challenging gas pairs such as C3H6/C3H8, demonstrating the high potential of this customizable post-regulation pore structure strategy. By post-tuning the GQD primitive membrane through heat treatment and in-situ crosslinking of small molecule amines, the as-prepared membrane achieved excellent CO2 separation performance and was further extended to the C3H6/C3H8 separation system.
Zhang et al. (Thu,) studied this question.