通过溶剂蒸发法得到聚酰胺酸(PAA)与氧化石墨烯(GO)的复合石墨烯膜,并经600℃炭化制备了具有良好柔韧性的仿贝壳珍珠层结构的自支撑石墨烯炭膜。通过X射线衍射和场发射扫描电镜对薄膜微观结构进行表征,并测试不同PAA固含量制备的石墨烯炭膜对CO2和CH_4的分离性能。结果表明,炭化后,GO被还原成石墨烯,呈层状堆叠,堆叠的层间填充了空穴和残炭;石墨烯炭膜的CO2渗透通量和CO2/CH4分离理想选择性随PAA加入量增加,CO_2通量最高可达824 barrer,此时CO2/CH4理想选择性达38.9。石墨烯层骨架和碳分子筛构成石墨烯炭膜的气体传输通道,本研究成果为柔性自支撑气体分离炭膜的制备开辟了新思路。
Free-standing graphene carbon membrane with conch nacre structure was prepared via carbonizing composite membrane of graphene oxide(GO) and polyamide acid(PAA) obtained by solvent evaporation method at 600℃. The morphology and structure were characterized by XRD and SEM. The permeation performance of CO_2 and CH4 of free-standing graphene carbon membrane with different PAA solid content was investigated. The results indicated that GO was thermally reduced to graphene in graphene carbon membrane after carbonization, in which graphene layers were lamellar stacked and gaps between layers were filled with holes and carbon residue. Both CO_2 permeability and ideal selectivity for the CO_2/CH4 of graphene carbon membranes were enhanced with increasing PAA solid content. The CO_2 flux of graphene carbon membrane was up to 824 barrer and the CO_2/ CH4 ideal selectivity reached 38.9 simultaneously. The gas permeation channels of graphene carbon membrane were attributed to the lamellar stacked of graphene and carbon molecule sieve in graphene carbon membrane. This study opened up new opportunities to prepare the flexible free-standing graphene carbon membrane for gas separation.