Enhancing dispersibility of nanofiller via polymer-modification for preparation of mixed matrix membrane with high CO2 separation performance

Mixed matrix membrane (MMM) is now emerging as a viable and promising option for industrial separation processes due to its combination of the benefits of polymers and porous nanofillers. However, the aggregation of nanofillers at high concentrations hinders the development of MMM. Here, we introduce a simple polymeric surface post-modification method by covalently bonding polyvinylamine (PVAm) to prepare polymer-modified Schiff base network-1 (SNW-1) called SNW-P. Adjusting the post-modification time improved the dispersibility of SNW-P. Compared to SNW-1, MMMs with SNW-P4H as nanofiller achieved a significantly high CO2 permeance of 3092 GPU as well as the CO2/N2 selectivity of 184 at the feed gas pressure of 0.2 MPa, which obviously surpasses the current limit enumerated by 2019. Additionally, for CO2/CH4 and CO2/H2 separation, the optimized membrane also exhibits excellent CO2 permeance. With low-cost raw materials and superior properties, the membrane created in our research has good potential for large-scale applications.