Adsorption kinetics in hierarchical porous carbide derived carbon materials

吸附过滤器是在生产过程中捕获有机蒸汽、去除气体原料中的少数成分、汽油回收、消除空气中的有毒微量气体以及气味管理等技术应用中的重要组成部分。对于多孔材料在过滤介质中的应用，不仅存储容量很重要。此外，许多过滤系统中的高气体速度需要高吸附速率，以避免毒素突破或有机蒸汽污染空气。在这种吸附过滤器中，高度需要含有在孔隙直径上变化几个数量级的互连孔隙系统的多孔材料。实现了一个定义良好的大孔（d >50 nm）系统，连接具有高吸附能力的微孔（d < 2 nm）网络，由于通过大孔系统的快速质量传输，保证了极高的吸附率。碳化物衍生碳（CDCs）是一类极具吸引力的新型多孔碳材料，具有极高的吸附能力和高达2800 m2/g的比表面积。在德累斯顿开发的铸造技术允许将适合捕获小气体分子的高微孔隙度与中孔甚至大孔二次孔隙结构相结合。如果使用合适的有序模板，聚合物前驱体的浇铸可以产生有序的介孔或大孔体系。该项目的重点是制备这种分级多孔碳化物衍生碳的吸附应用。主要目标是确定二次输送孔系统和相应的连接拓扑结构，以提高小分子（如碳氢化合物）的吸附速率。吸附率是通过突破性的研究，重力和光学（热辐射为基础）动力学吸附实验来确定的。选择了高吸附率的样品进行液相吸附和催化氧化测试，以证明分级孔结构的高性能水平。

Adsorption filters are essential components in technical applications for the capture of organic vapours in production processes, removal of minority components in gas feeds, gasoline recuperation, elimination of toxic trace gases from air, as well as odour management. For the application of porous materials in filter media not only the storage capacity is important. Moreover, high gas velocities in many filter systems require high adsorption rates to avoid breakthrough of toxins or air pollution with organic vapours. Porous materials containing interconnected pore systems varying several orders of magnitude in porediameter are highly desired in such adsorption filters. The realization of a well-defined macropore (d >50 nm) system connecting a network of micropores (d < 2 nm) with high adsorption capacity guarantees extremely high adsorption rates due to rapid mass transport through the macropore system. Carbide derived carbons (CDCs) are a novel attractive group of porous carbon materials with very high adsorption capacity and specific surface areas up to 2800 m2/g. Casting techniques developed in Dresden allow the combination of a high degree of microporosity suitable for capturing small gas molecules with either mesoporous or even macroporous secondary pore architectures. The casting of polymeric precursors can give rise to ordered meso- or macropore systems if suitable ordered templates are used. The project focuses on the preparation of such hierarchical porous carbide derived carbons for adsorption applications. A major goal is to identify secondary transport pore systems and the respective connectivity topologies to allow for an increased adsorption rate of small molecules such as hydrocarbons. The adsorption rate is determined using breakthrough studies, gravimetric, and optical (heat radiation based) kinetic adsorption experiments. Selected samples with high adsorption rate are also tested in liquid phase adsorption and catalytic oxidation in order to demonstrate the high performance level of hierarchical pore structures.