二氧化钛纳米粒子-氧化石墨烯/聚酰亚胺混合基质膜的原位聚合及气体渗透性能

Fabrication of TiO_2-GO/PI Mixed Matrix Membranes by In-situ Polymerization and Their Gas Permeation Property

以钛酸四丁酯为前驱体,采用浸渍-沉淀法制备二氧化钛纳米粒子-氧化石墨烯(TiO_2-GO)复合物,再将TiO_2-GO复合物与4,4'-(六氟异亚丙基)邻苯二甲酸酐和4,4'-二氨基二苯醚通过原位聚合构建TiO_2-GO/TiO_2-GO/PI(聚酰亚胺)混合基质膜,用于CO_2的渗透脱除.采用傅里叶变换红外光谱(FTIR)、拉曼光谱(Raman)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热失重(TG)和Zeta电位等表征了TiO_2-GO复合物和TiO_2-GO/PI混合基质膜的形貌与结构;探讨了TiO_2掺杂量对TiO_2-GO复合物及TiO_2-GO/PI混合基质膜的结构和气体渗透性能的影响.结果表明,TiO_2-GO复合物中TiO_2纳米粒子较均匀地沉积在GO片层上,TiO_2纳米粒子在形成的同时破坏了GO的结构,使其无序度增加.TiO_2的掺杂对TiO_2-GO/PI混合基质膜的形貌与结构影响较小,但提升了TiO_2-GO/PI混合基质膜的CO_2和N2渗透性能.但过量的掺杂使TiO_2粒子在GO片层上团聚,从而导致TiO_2-GO复合物在混合基质膜中的分散性变差,CO_2渗透性及CO_2/N2渗透选择性降低.当TiO_2掺杂质量分数为30%时,TiO_2-GO/PI混合基质膜的CO_2渗透性为360 Barrer[1 Barrer=10^(-10)cm^3(STP)·cm/(cm^2·s·cm Hg)=7.5×10^(-14)cm^3(STP)·cm/(cm^2·s·Pa)],CO_2/N_2的渗透选择性可达31.

Titanium dioxide-graphene oxide（ TiO2-GO） nanocomposites were synthesized by impregnationreduction method using tetrabutyl titanate（ C16H36O4Ti） as the source of TiO2,then TiO2-GO/polyimide（ TiO2-GO/PI） mixed matrix membranes were fabricated via in-situ polymerization with 4,4’-（ hexafluoroisopropylidene） diphthalic anhydride（ 6FDA）/4,4’-oxydianiline（ ODA）/TiO2-GO. The structures of TiO2-GO nanocomposites and TiO2-GO/PI mixed matrix membranes were characterized by Fourier transform infrared spectroscopy（ FTIR）,Raman spectroscopy and transmission electron microscopy（ TEM）,scanning electron microscope（ SEM）,thermo-gravimetric analysis（ TGA） and zeta potential instrument. The effects of TiO2-doping on the structure of TiO2-GO nanocomposites and TiO2-GO/PI mixed matrix membranes were discussed,and the gas permeation properties of the mixed matrix membranes were measured. The results reveal that TiO2 nanoparticles are impregnated uniformly in GO nanosheets,the dope of TiO2 would slightly destroy the structure of GO,and the disorder degree of GO structure increased. But the dope of TiO2 which was helpful to improve the dispersion of TiO2-GO nanocomposite in the mixed matrix membrane,thus enhance the gas permeation properties of the mixed matrix membrane. However,the excess of TiO2-doping would lead to the aggregation of TiO2 particles on the GO surface,which depressed the gas permeation properties of the mixed matrix membrane. When the mass fraction of TiO2-doping reached 15% in TiO2-GO nanocomposite,the mixed matrix membrane demonstrated good CO2 permeability and CO2/N2 permeation selectivity, and CO2 permeability was 360 Barrer,and CO2/N2 permeation selectivity reached 31.