Adjusting carrier microenvironment in CO2 separation fixed carrier membrane

•A method for adjusting carrier environment of fixed carrier membrane is introduced.•A membrane concurrently containing fixed amine and movable carbonate is prepared.•The membrane exhibits good permselectivity and favorable stability.

An ion-exchange material – Poly(diallyldimethylammonium carbonate) (PDDACA) containing mobile carbonate has been prepared and it has been blended in a fixed carrier membrane material – polyvinylamine (PVAm) containing abundant amine-group to adjust the carrier microenvironment of the fixed carrier membrane. It makes the mobile carrier cruise around the fixed carrier. On one hand, the CO2 can be transported continuously in the swing area of fixed carrier through the mobile carriers, the passivity of fixed carrier can be overcome and the utilization efficiency of fixed carrier can be enhanced. On the other hand, a loose and low crystalline system will be obtained by blending two polymers, the number of effective mobile carrier will be increased with mobile carriers unlocking from the crystalline area, and the loose and low crystalline system will provide a good environment for the movement of mobile carriers. These are conducive to enhance the performance of blend membrane in comparision with single polymer membrane. The CO2 permeance and CO2/N2 selectivity of PVAm-PDDACA membrane, which concurrently contains fixed amine carriers and movable carbonate carriers, can reach 909 GPU and 102 at 0.11 MPa, respectively. The performance of PVAm-PDDACA membrane is enhanced obviously in comparision with PVAm membrane and PDDACA membrane.