Novel open cell aluminum foams and their use as reactive support for zeolite crystallization
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Open cell aluminum (Al) foams are developed in this work by a novel direct foaming process in which a low concentrated alkane phase is emulsified in a stabilized Al powder suspension. In this versatile technique, the porosity parameters are adjusted during foaming of the emulsified suspensions and the final stability is achieved by a thermal treatment above the melting temperature of Al. The thin oxide layers surrounding the Al particles and the ascertained percolation of the molten metal are essential in this stage. The efficiency of the processing route is demonstrated with the essential requisites for successful foaming and the final structural stability. Furthermore, open cell Al-foams/zeolite composites exhibiting a hierarchical porous structure (nano- and macroscale) are produced by hydrothermal synthesis of Faujasite-like zeolite on the surface of the developed Al-foams. Due to the advantageous properties of zeolite X in N2 adsorption, the application of the composites for separation of N2 from air is specially envisaged.
KeywordsAl foams Highly porous materials Zeolite
The authors would like to thank the AiF for funding parts of this work within the project “Multifunktionelle Keramikschäume 14260 N”. The assistance of Hailing Wang concerning the practical work is also gratefully appreciated. The authors A. Schwab and W. Schwieger also gratefully acknowledge the funding of the German Research Council (DFG), which, within the framework of its ‘Excellence Initiative’ supports the Cluster of Excellence ‘Engineering of Advanced Materials’ (www.eam.uni-erlangen.de) at the University of Erlangen-Nuremberg.
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