高渗透性石墨烯杂化炭膜的制备及表征

Preparation and characterization of graphene hybrid carbon membranes with high permeability

以4,4′-二氨基二苯醚-3,3′,4,4′-二苯甲酮四酸二酐(BTDA-ODA)型聚酰亚胺为前体,石墨烯为掺杂剂,经共混、成膜、干燥和热解过程制备杂化炭膜.采用热失重、扫描电镜、X射线衍射、红外光谱及渗透等技术分别对前体热稳定性、炭膜微观形貌、微观结构、表面基团和气体分离性能进行分析.考察了石墨烯含量对炭膜微结构与性能的影响,结果显示,引入石墨烯使前体热稳定性提高;石墨烯与炭膜母体间兼容性良好,在大幅度提高气体渗透性同时保持了较好的分子筛分能力;掺杂石墨烯后,使炭膜对H_2,CO_2与O_2的渗透性分别提高了6.8倍,46倍和59倍.当石墨烯质量分数为0.5%时,杂化炭膜对CO_2渗透性达1 236.7Barrer,此时CO_2/N_2选择性达24.1,具有较好的应用前景.

Hybrid carbon membranes were prepared by using 4,4′-diaminodiphenyl ether-3,3′,4,4′-benzophenone tetracarboxylic dianhydride（BTDA-ODA）polyimide as precursor and graphene as dopant,via the processes of blending,membrane-forming,drying and pyrolysis.The TG（thermogravimetry）,SEM（scannin electron microscope）,XRD（X-ray diffraction）,IR（infrared spectroscopy）and gas permeation technique were respectively applied to characterize the thermal stability of precursor,and the morphology, microstructure,surface chemical moieties and separation performance of the carbon membranes.The effects of graphene content on the microstructure and properties of carbon membrane were investigated.The results show that the introduction of graphene can lead to the enhancement of thermal stability of precursors.The resultant hybrid carbon membranes have both excellent permeability and molecular sieving ability due to the fairly well compatibility between graphene and membrane matrix.The gas permeabilities of hybrid carbon membranes are respectively increased by 6.8times for H2,46 times for CO2 and 59 times for O2.When the mass fraction of graphene is 0.5%,the hybrid carbon membranes reveal attractive gas separation performance commercially,i.e.,CO2 permeability of 1 236.7Barrer and CO2/N2 selectivity of 24.1.