Abstract In this paper an attempt is made to review the progress in membrane characterization and transport theory in historical perspective. Its central theme is the membrane “pore” around which progress has been revolving, irrespective of whether the researcher is “for” or “against” the existence of pores at the top dense layer of the RO membrane. The article starts from nineteen-fifties when the development of cellulose acetate membrane was launched on the basis of the Preferential Sorption-Capillary Flow (PS-CF) mechanism. The Sorption-Diffusion (S-D) model, which was presented at almost the same time, regards the top surface layer dense and homogeneous. No heterogeneity is allowed and the presence of pores makes the RO membrane imperfect, causing the leakage of salt. Thus, the PS-CF model came to direct confrontation with the S-D model. It is shown in this brief historic review how the advanced characterization instrument has revealed the heterogeneous structure of the top surface of the RO membrane and measured its “pore size” and “pore size distribution”. The advanced transport theory based on Molecular Dynamics (MD) simulation also resulted in the presence of the multi-modal pore size distribution.

中文翻译：

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近五十年反渗透（RO）膜传输理论与表征方法进展

摘要 本文试图从历史的角度回顾膜表征和传输理论的进展。它的中心主题是膜“孔”，无论研究人员是“支持”还是“反对”RO 膜顶部致密层的孔的存在，进展一直围绕着膜“孔”。文章从十九世纪五十年代开始，基于优先吸附-毛细管流动（PS-CF）机理开始开发醋酸纤维素膜。几乎同时提出的吸附-扩散 (SD) 模型认为顶面层致密且均质。不允许有异质性，孔隙的存在使 RO 膜不完美，导致盐的泄漏。因此，PS-CF 模型开始与 SD 模型直接对抗。这篇简短的历史回顾展示了先进的表征仪器如何揭示 RO 膜顶面的异质结构并测量其“孔径”和“孔径分布”。基于分子动力学 (MD) 模拟的先进输运理论也导致了多模态孔径分布的存在。