含聚乙烯基胺共混固定载体复合膜制备及其CO_2/CH_4分离性能

Preparation of blend fixed carrier membranes containing polyvinylamine and its CO_2/CH_4 separation performance

通过溶液共混法制备了聚乙烯基胺(PVAm)/聚乙二醇(PEG)和PVAm/聚N乙烯基γ氨基丁酸钠(PVSA)共混聚合物.分别以这两种共混聚合物为分离层,以聚醚砜超滤膜为支撑层制备了用于分离CO2的固定载体复合膜.研究了共混组成对膜结构和性能的影响,结果表明共混可以改善固定载体膜的透过分离性能.PEG质量含量为10%的PVAm/PEG共混膜具有整体最优的透过分离性能,当温度为25℃、压力为125kPa时,纯CO2渗透速率为4.34×10-9cm3(STP)·cm-2·s-1·Pa-1,CO2/CH4理想分离因子为63.5;对PVAm/PVSA共混膜,PVSA质量含量为33.3%的膜具有最高的CO2/CH4理想分离因子,而PVSA质量含量为50%的膜具有最高纯CO2渗透速率.

Polyvinylamine （ PVAm ）/polyethylene glycol （ PEG ） and PVAm/Poly （ N-vinyl-）＇-sodium aminobutyrate） （PVSA） polymer blends were prepared in this study. Composite membranes for the facilitated transport of CO2 were prepared by using the dip-coating process with polymer blends as separation layer and polyethersulfone ultrafiltration membrane as substrate. The effects of blending composition on the structure and performance of the membranes were investigated by testing the crystallinity and gas permselectivity of membrane. The results showed that the proper blending of PVAm with PEG could reduce the membrane crystallinity and increase the effective permeation area and carrier content. The membrane with 10% （mass） PEG has the highest pure CO2 permeation rate of 4.2）〈10^-9 cm^3 （STP）·cm^-2·s^-1·Pa^-1 and highest CO2/CH4 ideal selectivity of 63.1 at 25℃ and 122.7 kPa of feed pressure. As for the PVAm/PVSA blend membrane, a proper blending composition could also improve the permselectivity of membrane. The membrane with 33 % （mass） PVSA showed the highest CO2/CH4 ideal selectivity, while the membrane with 50% （mass） PVSA possessed the highest CO2 permeation rate.