An in-situ Pore-Size Distribution Determination Technique Based on the Capillary Phase Separation in Liquid Phase

我们开发了一种测定浸没在液体中可能膨胀的多孔固体的孔径分布的技术，正如它在浸没状态下所显示的那样。该技术采用毛细管相分离，即细孔内相分离，即使浓度低于饱和浓度。我们可以通过测量合适溶质或探针分子的液相吸附等温线来计算原位孔径分布。通过研究，得出以下结论：1。测定了水溶液中芳香族化合物在多孔固体上的液相吸附等温线。还测量了固体的氮等温线，以获得它们的表面积和孔径分布。2.采用与多孔固体具有相同化学成分的非多孔固体来获得这些固体在液相中的表面吸附量。测定了氮吸附等温线。3.根据上述数据，分别从液相吸附数据和氮吸附数据计算孔径分布。这两个分布很好地吻合，证明了本方法的有效性。4.为使该技术应用于膨胀/收缩材料，已经进行了一些研究。我们发现所谓的无模型方法在没有表面吸附数据的情况下也能合理地找到孔径特征。5.此外，合适的探针分子是环烷烃，尤其是环戊烷。6.除了水系统，该技术已被证明在一些非水溶剂系统中是有效的。综上所述，本项目建立了一种原位测量液体中多孔固体孔隙尺寸分布的技术，这是传统方法如氮吸附法和汞孔隙度法无法检测到的。

We developed a technique for the determination of pore-size distribution of immersed porous solids, which may swell in liquid, as it shows in the immersed state. The capillary phase separation, or a phase separation within fine pores even at a lower concentration than the saturated concentration, was utilized in the technique. We can calculate an in-situ pore size distribution from a measured liquid-phase adsorption isotherm of a suitable solute, or a probe molecule. Through the research, the following was concluded.1.Liquid-phase adsorption isotherms of some aromatic compounds from aqueous solution onto some porous solids were measured. Nitrogen isotherms of the solids were also measured to obtain their surface areas and pore size distributions. 2.Nonporous solids which have the same chemical composition as those of porous solids were employed to obtain the amount of surface adsorption in liquid phase onto these solids. Nitrogen adsorption isotherms were also measured. 3.From the data mentioned above, pore size distributions were calculated both from liquid phase adsorption data and from nitrogen adsorption data. The two distributions agreed well to prove the validity of the present technique. 4.Some studies have been carried out to brush up this technique for the application to swelling/shrinking materials. We have found the so-called Modelless Method can find pore size characteristics reasonably even if no data of surface adsorption is available. 5.Further, suitable probe molecules were found to be cyclic alkanes, especially cyclopentane. 6.Other than aqueous systems, this technique has been proven to be effective in some systems with non-aqueous solvents.Summarizing, a technique to measure in-situ pore size distribution of porous solids in liquid, which could never been detectable by conventional methods such as nitrogen adsorption and mercury porosimetry, has been established through this research project.