Development of selective nanofiltration membranes based on nanoporous organic frameworks

现代膜技术在能源和成本高效的分离过程中具有巨大的潜力。特别是针对未来生物精炼过程的选择性纳滤技术的发展，需要新的膜材料，以及对这些膜材料和待分离物质的结构-性质-关系的基本了解。近年来引起人们极大关注的新型纳米多孔聚合物和有机骨架具有巨大的潜力。它们是很有前途的分离材料，因为各种孔性质以及内表面的极性都可以定制。本项目的目的是开发基于系统优化的纳米孔聚合物的混合基质膜，并研究其在纳滤分离水溶液中应用相关的模型体系5-羟甲基呋喃(HMF)/果糖的应用。其中一个焦点是新材料的开发。除了使用参考材料外，还将开发一种新的、可扩展的元素有机骨架合成路线，使用格氏结构代替有机锂中间体。由于反应性降低，骨架结构的形成得到了更好的控制，从而能够对孔性能以及内表面化学进行裁剪。通过系统地改变连接器的种类，可以合成一系列具有不同表面极性的材料。对HMF和果糖在水溶液中的液相吸附行为进行了实验研究，以评价结构-性质-关系，这是发展液相分离技术所必需的。最终，合成的聚合物以细小的不可溶粉末的形式出现，被加工成混合基质膜。在HMF/果糖混合水溶液的纳滤中考察了它们的分离性能。总体而言，该项目结合了以新型多孔材料及其在生物平台化学品液相吸附中的结构-性能-关系为重点的基础研究，以及基于膜纳滤的新分离技术的应用相关开发，用于未来的生物精炼概念。

Modern membrane technologies possess great potential for energy- and cost-efficient separation processes. Especially the development of selective nanofiltration technologies for future bio-refinery processes requires new membrane materials as well as a basic understanding of the structure-property-relations of those and the substances to be separated. Novel nanoporous polymers and organic frameworks, which have attracted considerable attention in recent years, offer great potential. They are promising materials for separation since various pore properties as well as the polarity of the inner surface can be tailored. The aim of this project is the development of mixed matrix membranes based on systematically optimized nanoporous polymers and their investigation in the separation of the application-related model system 5-hydroxymethylfurfural (HMF)/fructose in aqueous solution by nanofiltration. One focus is the development of novel materials. Besides using reference materials, a new and scalable synthesis route for element organic frameworks is to be developed, using a Grignard instead of an organolithium intermediate. Due to the decreased reactivity the formation of the framework structure is better controlled, thus, enabling the tailoring of the pore properties as well as the inner surface chemistry. By a systematic variation of the connector species a series of materials with varying surface polarity are to be synthesized. Experiments on the liquid phase adsorption behavior of HMF and fructose from aqueous solutions are conducted to evaluate structure-property-relations, which are essential for separation technology development in liquid phase processing. Ultimately, the synthesized polymers, occurring as fine and non-soluble powders, are processed to mixed matrix membranes. Their separation performance is investigated in the nanofiltration of HMF/fructose aqueous mixtures. Overall, the project combines basic research focused on the field of novel porous materials and their structure-property-relations in liquid phase adsorption of biogenic platform chemicals with the application-related development of new separation technologies based on membrane nanofiltration for future biorefinery concepts.