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气、去除气体原料中的少数组分、汽油回收、消除空气中有毒痕量气体以及气味管理的技术应用中的基本部件。对于多孔材料在过滤介质中的应用来说，不仅存储容量很重要。此外，许多过滤系统中的高气速要求高吸附速率，以避免毒素或有机蒸气对空气的污染。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相互连接的孔系统的多孔材料。一个定义明确的大孔(d&gt；50 nm)系统的实现将具有高吸附能力的微孔(d&lt；2 nm)网络连接在一起，由于通过大孔系统的快速质量传输，确保了极高的吸附速率。碳化物衍生碳(CDCs)是一类极具吸引力的新型多孔炭材料，具有非常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高度的微孔率适合于捕获小气体分子与介孔甚至大孔次级孔结构相结合。如果使用适当的有序模板，聚合物前驱体的浇注可以产生有序的中孔或大孔系统。该项目的重点是制备这种用于吸附应用的分级多孔碳化物衍生碳。一个主要目标是确定二次传输孔系统和各自的连通性拓扑结构，以提高碳氢化合物等小分子的吸附速率。通过突破性研究、重量法和光学(基于热辐射)动力学吸附实验确定了吸附速率。选定的高吸附速率的样品还进行了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.