MXene/rGO中空纤维复合膜的构建及气体分离性能

Construction and gas separation performance of MXene/rGO hollow fiber composite membranes

通过聚二烯丙基二甲基氯化铵(PDDA)对rGO表面进行修饰,表面带有正电荷的柔性rGO纳米片插层带有负电的MXene纳米片之间以调控层间距,形成排列良好的交替有序2D-2D复合结构,采用真空辅助抽滤法在Al_(2)O_(3)中空纤维沉积制备中空纤维MXene/rGO复合膜.采用扫描电子显微镜(SEM)对MXene/rGO复合膜进行表面微观形貌分析,通过X射线衍射仪(XRD)和X射线衍射光电子能谱仪(XPS)进行层间距、化学晶型分析和元素价态分析,对膜结构和表面的带电性及气体渗透性进行测试.结果表明:表面带有正电荷的rGO作为插层材料,可调控MXene纳米片层间距至3.15A,介于H_(2)(2.89A)和CO_(2)(3.30A)分子动力学直径之间,从而提高MXene/rGO复合膜的分离性能.25℃时,MXene/rGO复合膜的H_(2)渗透率为5.13×10^(-8)mol/(m^(2)·s·Pa),H_(2)/CO_(2)选择性为125.同时经过200 h的膜稳定性测试,MXene/rGO复合膜表现出优秀的稳定性.

MXene/rGO composite membranes were prepared through rGO modified by polyallyl dimethyl ammonium chloride(PDDA)inserted into the MXene nano-sheet with negative charge to inhibit the selfstacking of MXene.Scanning electron microscopy(SEM)was used to analyze the surface morphology of MXene/rGO composite membranes.X-ray diffraction(XRD)and X-ray diffraction photoelectron spectroscopy(XPS)were used to analyze the layer spacing,chemical crystal pattern and valence state of elements.The results show that MXene/rGO can achieve inter-spacing of 3.15 A through intercalating regulation.Moreover,MXene/rGO composite hollow fiber membranes show excellent H_(2) permeance of 5.13×10^(-8) mol/(m^(2)·s·Pa),H_(2)/CO_(2) selectivity of 125 at 25℃,and excellent stability over 200 h.