Abstract Graphene oxide (GO) membranes offer attractive gas separation properties. However, the gas separation mechanism for GO membranes is unclear due to inconsistent permeation and separation results reported in the literature. In this work, pure gas permeation and separation of equimolar (H2/CO2) mixture experiments were conducted on GO membranes made from large GO sheets of different sizes (33 and 17 µm) to understand the gas permeation and separation characteristics of these membranes. At room temperature the permeation of large molecules (CH4, N2 and CO2,) through GO membranes exhibits Knudsen–like diffusion characteristics, with the permeance for the small sheet GO membrane about twice that for the large sheet GO membrane. The smaller gases (H2 and He) exhibit much higher permeance, showing additional transport in additional pathway. The GO membranes show good H2/CO2 selectivity for both pure and binary gas feeds, without CO2 pore blockage effect for mixture separation found for crystalline microporous membranes. An inter-sheet and inner-sheet two-pathway model is proposed which can explain the results obtained in this work. Gas permeation in GO membranes, more complex than in crystalline microporous membranes, is determined by solubility (surface properties), diffusivity (relative molecular size to pore size), porosity and tortuosity of both the inter-sheet pores and inner-sheet defect pores. These properties are strongly influenced by synthesis method and conditions for GO sheets and membranes.

中文翻译：

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大片堆叠氧化石墨烯膜的气体渗透和分离性能

摘要 氧化石墨烯 (GO) 膜具有吸引人的气体分离特性。然而，由于文献报道的渗透和分离结果不一致，GO膜的气体分离机制尚不清楚。在这项工作中，在由不同尺寸（33 和 17 µm）的大 GO 片制成的 GO 膜上进行了等摩尔（H2/CO2）混合物的纯气体渗透和分离实验，以了解这些膜的气体渗透和分离特性。在室温下，大分子（CH4、N2 和 CO2）通过 GO 膜的渗透表现出类似 Knudsen 的扩散特性，小片状 GO 膜的渗透性约为大片状 GO 膜的两倍。较小的气体（H2 和 He）表现出更高的渗透性，显示出额外的传输途径。GO 膜对纯气体进料和二元气体进料均显示出良好的 H2/CO2 选择性，没有结晶微孔膜对混合物分离的 CO2 孔堵塞效应。提出了一个片间和内片双通路模型，可以解释在这项工作中获得的结果。GO 膜中的气体渗透比结晶微孔膜更复杂，由溶解度（表面特性）、扩散率（相对分子尺寸与孔径）、孔隙率和弯曲度决定，片间孔和片内缺陷孔。这些特性受 GO 片材和膜的合成方法和条件的强烈影响。提出了一个片间和内片双通路模型，可以解释在这项工作中获得的结果。GO 膜中的气体渗透比结晶微孔膜更复杂，由溶解度（表面特性）、扩散率（相对分子尺寸与孔径）、孔隙率和弯曲度决定，片间孔和片内缺陷孔。这些特性受 GO 片材和膜的合成方法和条件的强烈影响。提出了一个片间和内片双通路模型，可以解释在这项工作中获得的结果。GO 膜中的气体渗透比结晶微孔膜更复杂，由溶解度（表面特性）、扩散率（相对分子尺寸与孔径）、孔隙率和弯曲度决定，片间孔和片内缺陷孔。这些特性受 GO 片材和膜的合成方法和条件的强烈影响。片间孔和片内缺陷孔的孔隙率和曲折度。这些特性受 GO 片材和膜的合成方法和条件的强烈影响。片间孔和片内缺陷孔的孔隙率和曲折度。这些特性受 GO 片材和膜的合成方法和条件的强烈影响。