Adsorption kinetics in hierarchical porous carbide derived carbon materials

吸附过滤器是技术应用中的重要组成部分，用于捕获生产过程中的有机蒸汽，去除气体进料中的少数组分，汽油回收，消除空气中的有毒微量气体以及气味管理。对于多孔材料在过滤介质中的应用，不仅存储容量是重要的。此外，许多过滤器系统中的高气体速度需要高吸附速率以避免有机蒸气穿透毒素或空气污染。在这种吸附过滤器中，非常需要含有孔径变化几个数量级的互连孔系统的多孔材料。由于通过大孔系统的快速传质，连接具有高吸附能力的微孔（d < 2 nm）网络的明确限定的大孔（d >50 nm）系统的实现保证了极高的吸附速率。碳化物衍生炭（Carbide derived carbon，CDC）是一类新型多孔炭材料，具有很高的吸附容量和比表面积，可达2800 m2/g。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度微孔与中孔甚至大孔二级孔结构相结合。如果使用合适的有序模板，聚合物前体的浇铸可以产生有序的中孔或大孔体系。该项目的重点是制备用于吸附应用的这种分级多孔碳化物衍生碳。一个主要的目标是确定二级运输孔隙系统和相应的连接拓扑结构，以允许增加的吸附速率的小分子，如烃。吸附率测定使用突破研究，重量分析，和光学（热辐射为基础的）动力学吸附实验。选择具有高吸附率的样品也在液相吸附和催化氧化中进行了测试，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.