Enhanced Performance of a Novel Polyvinyl Amine/Chitosan/Graphene Oxide Mixed Matrix Membrane for CO2 Capture

In this study, a facilitated transport mixed matrix membrane was fabricated by a surface coating method. Polyvinyl amine (PVAm) and chitosan (Cs) were used as the polymer matrix materials and coated onto a porous polysulfone (PS) support. Graphene oxide (GO) grafted with hyperbranched polyethylenimine (HPEI-GO) was added as the nanofiller. The gas separation tests with CO2/N-2 (10:90 v:v) mixed gas suggest that the addition of GO could improve CO2/N-2 selectivity. The highest CO2 permeance was 36 GPU in the membrane with 2.0 wt % HPEI-GO, and the optimal selectivity was 107 in the membrane with 3.0 wt % HPEI-GO. Herein, GO could provide a transport channel for CO2 and enhance the long-term stability of the membranes Further gas separation tests under various relative humidities confirmed that facilitated transport was the main mechanism of gas separation through the membrane. The stability test suggests that the membrane has long-term stability. CO2 transports through the membrane mainly by the facilitated transport mechanism with assistance from the solution diffusion mechanism, while N-2 transports only by the solution-diffusion mechanism.