Mechanical Synthesis of COF Nanosheet Cluster and Its Mixed Matrix Membrane for Efficient CO2 Removal.

Covalent organic framework (COF) membranes used for selective removal of CO2 were believed as an efficient and low-cost solution to energy and environmental sustainability. In this study, the amide modified COF nanosheet cluster with a 2D structure was facilely prepared through solid reaction, exhibiting good adsorption-based CO2 selectivity (223 at 273 K and 90 at 298 K) toward N2. Remarkably, the mixed matrix membrane (MMM) that consists of a lesser amount of COF filler (1 wt %) shows promising CO2/N2 gas selectivity (∼64). In addition, the competitive adsorption prompts the selectivity to ∼72 under an equimolar CO2/N2 mixture, which surpasses the values of all reported COF membranes. It is worth to note that the binary gas separation is stable during 120 h.