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以聚砜(PS)超滤膜为支撑层,首先制备聚乙烯基胺(PVAm)/聚乙烯醇(PVA)复合膜,考察PVAm与PVA的组成及铸膜液固含量对膜渗透选择性能的影响.当PVAm/PVA为7/3,固含质量分数为8％时,复合膜的性能最好,0.2 MPa下,CO2渗透速率为35.5 GPU[1GPU=10-6 cm3(STP)/(cm2·s· cmHg)],CO2/N2的分离系数为123.6.其次,在上述最佳条件中添加不同类型的多壁碳纳米管(MWCNT、MWCNT-OH和MWCNT-COOH),考察碳纳米管含量及表面基团对气体分离性能的影响,并利用红外分析、X-射线衍射及扫描电镜考察所制备杂化膜的化学结构、结晶性能.结果表明,添加表面-OH和-COOH改性的MWCNT可以有效提高膜的透过分离性能.当MWCNT-OH和MWCNT-COOH质量分数均为1％时,CO2渗透速率分别为62.0和76.6 GPU,CO2/N2的分离系数分别为117.7和139.5.最后,考察进料气压力对杂化膜CO2渗透速率及CO2/N2的分离系数的影响,在0.2～1.8 MPa的压力范围内,添加表面改性的碳纳米管均能使复合膜的CO2渗透速率提高.

In this paper,the polyvinyl amine (PVAm)/polyvinyl alcohol (PVA) composite membrane was prepared by physical mixing and solution casting on a polysulfone (PSf) support membrane.The effects of the ratio of PVAm to PVA and the casting solution concentration on permselectivity were studied.When the ratio of PVAm and PVA was 7/3 and concentration of casting solution was 8％,the composite membrane possessed CO2 permeance of 35.5 GPU [1 GPU=1 × 10-6 cm3 (STP)/(cm2 · s · cmHg)] and CO2/N2 selectivity of 123.6 under the condition of 0.2 MPa.Doping different types of multiwall carbon nanotube (MWCNT) under the above optimal condition,the influences of MWCNT content and surface group were investigated.The chemical construction and crystallization property of mixed matrix membrane were characterized by IR,XRD and SEM.The gas permselectivity testing results indicated that the membrane performance can be improved availably by adding MWCNT modified with-OH and-COOH.While the amount of both MWCNT-OH and MWCNT-COOH are 1％,the CO2 permeances can reach 62.0 GPU and 76.6 GPU,and CO2/N2 selectivity are 117.7 and 139.5,respectively.Finally,the impacts of feed pressure on CO2 permeance and CO2/N2 selectivity were explored.It was found that the CO2 permeance increased obviously with adding the MWCNT-OH and MWCNT-COOH when the pressure ranged from 0.2 MPa to 1.8 MPa.