Liu Zhongyun, Qiu Wulin, Koros William J
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Dr. NW, Atlanta, GA 30332, USA.
Angew Chem Int Ed Engl. 2022 Nov 7;61(45):e202210831. doi: 10.1002/anie.202210831. Epub 2022 Oct 10.
Carbon molecular sieve (CMS) membranes offer the best available combination of scalable economical processability with excellent separation performance. Physical aging of CMS membranes causes pore structure changes over time that affect CMS membrane performance. To provide fundamental insights into the structure evolution in CMS membranes during physical aging, a combined dual-mode sorption and transport model is used in this study to characterize the diffusion coefficients of gas molecules in fresh and 7-day vacuum aged CMS membranes. The results show physical aging of CMS membrane is primarily "diffusion related" and such aging behavior simultaneously causes ultramicropore changes in the continuous phase and Langmuir phase of CMS membrane. The new insights offered in this study suggest strategies to control the physical aging of CMS membranes and even use it as a valuable tool to tune the separation performance of CMS membranes for demanding gas separations.
碳分子筛（CMS）膜具备可扩展的经济可加工性与出色分离性能的最佳组合。CMS膜的物理老化会导致孔结构随时间变化，从而影响CMS膜的性能。为了深入了解CMS膜在物理老化过程中的结构演变，本研究采用了一种结合双模式吸附和传输的模型来表征气体分子在新鲜的和经过7天真空老化的CMS膜中的扩散系数。结果表明，CMS膜的物理老化主要是“与扩散相关的”，并且这种老化行为同时会导致CMS膜连续相和朗缪尔相中的超微孔发生变化。本研究提供的新见解提出了控制CMS膜物理老化的策略，甚至可将其用作调整CMS膜分离性能以满足苛刻气体分离要求的宝贵工具。
