聚醚共聚酰胺多层复合气体分离膜的制备及其分离性能

采用浸渍涂覆法,以聚醚共聚酰胺PEBA1074嵌段高分子为选择层膜材料制备具有超薄分离层的PEI/PDMS/PEBA1074/PDMS多层复合气体分离膜,探讨了操作条件对H2、N2、CH4和CO2等在多层复合膜中的渗透性能的影响.多层复合膜对极性气体具有较高的渗透通量,并且对极性/非极性气体分离体系具有较高的选择性.CO2对多层复合膜存在增塑作用,其渗透通量随操作压力的增加而增加;随着操作温度的升高,H2、N2、CH4和CO2在复合膜中的渗透通量显著增大,而CO2/非极性气体(H2、N2和CH4)的分离系数减小.气体渗透通量与温度的关系在PEO链段熔点的上下分别满足不同的Arrhenius方程.当操作温度大于PEO链段熔点温度时,气体的渗透活化能减小.

Preparation of multilayer poly(amide-12-b-ethylene oxide) composite membrane and their performance for gas separation

Block copolymer poly(amide-12-b-ethylene oxide)(PEBA1074) is used to fabricate multilayer polyetherimide(PEI)/polydimethylsilicone(PDMS)/PEBA1074/PDMS composite membranes by dip-coating method.The effects of operating conditions on the performance of the multilayer composite membranes are investigated.PEI/PDMS/PEBA1074/PDMS composite membranes show high permeance for polar gases and high ideal selectivity for polar/nonpolar gas systems.Due to CO2 induced plasticization effect,the CO2 permeance increases with increasing pressure.When temperature increases,the permeance of CO2,N2,H2,and CH4 through the composite membrane increases,while the selectivity of CO2/nonpolar gas(N2,H2,and CH4) decreases.The temperature dependency of gas permeance can be expressed by different Arrhenius equations below and above the melting temperature of PEO.The apparent activation energies of permeation decreases when the operation temperature is above the melting temperature of PEO.