摘要
Integrally skinned asymmetric gas separation membranes of polyethersulfone(PES)/polyurethane(PU) blend were prepared using supercritical CO_2(SC-CO_2) as a nonsolvent for the polymer solution. The membrane consisted of a dense and a porous layer, which were conjoined to separate CO_2 from CH_4. The FTIR, DSC, tensile and SEM tests were performed to study and characterize the membranes. The results revealed that an increase in SC-CO_2 temperature causes an increment in permeance and a decrease in membrane selectivity. Furthermore,by raising the pressure, both permeance and selectivity increased. The modified membrane with SC-CO_2 had much higher selectivity, about 5.5 times superior to the non-modified membrane. This higher selectivity performance compared to previous works was obtained by taking the advantages of both using partial miscible blend polymer due to the strong polar–polar interaction between PU PES and SC-CO_2 to fabricate the membrane. The response surface methodology(RSM) was applied to find the relationships between several explanatory variables and CO_2 and CH_4 permeance and CO_2/CH_4 selectivity as responses. Finally, the results were validated with the experimental data, which the model results were in good agreement with the available experimental data.
Integrally skinned asymmetric gas separation membranes of polyethersulfone(PES)/polyurethane(PU) blend were prepared using supercritical CO_2(SC-CO_2) as a nonsolvent for the polymer solution. The membrane consisted of a dense and a porous layer, which were conjoined to separate CO_2 from CH_4. The FTIR, DSC, tensile and SEM tests were performed to study and characterize the membranes. The results revealed that an increase in SC-CO_2 temperature causes an increment in permeance and a decrease in membrane selectivity. Furthermore,by raising the pressure, both permeance and selectivity increased. The modified membrane with SC-CO_2 had much higher selectivity, about 5.5 times superior to the non-modified membrane. This higher selectivity performance compared to previous works was obtained by taking the advantages of both using partial miscible blend polymer due to the strong polar–polar interaction between PU PES and SC-CO_2 to fabricate the membrane. The response surface methodology(RSM) was applied to find the relationships between several explanatory variables and CO_2 and CH_4 permeance and CO_2/CH_4 selectivity as responses. Finally, the results were validated with the experimental data, which the model results were in good agreement with the available experimental data.
