Morphological characterization and transport properties of physically reconstructed chromatographic beds

定量形态-输运关系在开发更高效的功能材料的挑战中发挥着关键作用。有针对性的效率优化需要了解多孔固体的制备、形态和质量传输如何相关。该项目的重点是表征物理重构吸附剂（固定床）的形态和传输特性，这代表了小二氧化硅颗粒（< 3 µm），二氧化硅基整体柱和有机聚合物整体柱液相色谱的最新发展和问题（挑战）。的三维重建是基于实验颗粒和单片固定床，这已被常规制备的颗粒床的填充过程和单片的合成协议。这一方面很重要，因为它提供了透明度，独创性，并在这个项目所遵循的方法和所获得的结果的一致性。直接在重建的孔隙空间中模拟流体流动和质量传输允许基于材料的固有形态异质性和由此产生的流动分布不均-从微观孔隙尺度到宏观床尺度来表征时空动态。从孔隙空间的几何和拓扑分析中提取的参数实现了形态非均质性的量化。我们分析的形状，尺寸分布和孔隙的互连性，其中流体流动和平流运输占主导地位，以及空间域，其中扩散运输和吸附占主导地位，如在停滞区域内的颗粒（或整料骨架）。该项目的目标是通过对无序孔隙空间的几何和拓扑分析，结合详细的孔隙尺度流动和质量传输模拟，确定有效扩散传输的形态描述符，特别是色谱上更相关的流体动力学分散。从扩散/吸附限制质量传输的空间域到流场占主导地位的区域，我们用形态描述符定量评估它们的结构异质性。这类似地进行扩散/吸附，流动和传质的模拟和导出的传输系数，这反映了这种结构的异质性。因此，色谱实践的中心传输特性可以与形态学特性相关，形态学特性本身反映了吸附剂的填充过程或合成方案。这种互补的方法使我们能够识别敏感的形态描述符（通过详细的输运模拟验证），这将在未来指导从合成到基于物理重建的目标应用的材料特性的系统优化。

Quantitative morphology-transport relationships play a key role in the challenge to develop ever more efficient functional materials. Targeted optimization of efficiency requires knowledge on how preparation, morphology, and mass transport of a porous solid are related. In the focus of this project is the characterization of morphological and transport properties of physically reconstructed adsorbents (fixed beds), which represent the latest developments and problems (challenges) in liquid chromatography with small silica-based particles (< 3 µm), silica-based monoliths, and organic polymer-monoliths. The three-dimensional reconstructions are based on experimental particulate and monolithic fixed beds, which have been conventionally prepared regarding the packing process of the particulate beds and the synthesis protocol of the monoliths. This aspect is important as it provides transparency, originality, and genuity to the methodology followed in this project and the obtained results. Simulations of fluid flow and mass transport directly in the reconstructed pore spaces allow the characterization of spatiotemporal dynamics based on the intrinsic morphological heterogeneity of the materials and resulting flow maldistribution - from the microscopic pore scale up to the macroscopic bed scale. The quantification of morphological heterogeneity is achieved with parameters extracted from the geometrical and topological analysis of the pore spaces. We analyze shape, size distribution, and interconnectivity of the pores, in which fluid flow and advective transport dominate, as well as spatial domains, in which diffusive transport and adsorption prevail, like in stagnant regions inside the particles (or a monolith skeleton). The goal of this project is to identify morphological descriptors for effective diffusive transport and especially the chromatographically far more relevant hydrodynamic dispersion through the geometrical and topological analysis of the disordered pore spaces in combination with the detailed pore scale simulations of flow and mass transport. From spatial domains, in which diffusion/adsorption limit mass transport, to regions, in which the flow field dominates, we quantitatively assess their structural heterogeneity with morphological descriptors. This proceeds analogously in the simulations of diffusion/adsorption, flow, and mass transport and derived transport coefficients, which reflect this structural heterogeneity. Consequently, transport properties central to chromatographic practice can be correlated with morphological properties, which themselves reflect the packing process or synthesis protocol of an adsorbent. This complementary approach allows us to identify sensitive morphological descriptors (validated through the detailed transport simulations), which in the future will direct the systematic optimization of material properties from the synthesis to targeted applications based on physical reconstruction.