Adsorption kinetics in hierarchical porous carbide derived carbon materials

• Applicant: Professor Dr. Stefan Kaskel
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 224953578

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.

• DFG Programme: Research Grants