Synthesis of Zeolite Crystallites for Diffusion Measurement

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The work of this project is devoted to the determination of the diffusivities resulting from permeation measurements (i. e. of macroscopic and mesoscopic transport diffusivities measured under stationary conditions) for comparison with the diffusivities of comparable systems obtained by the other techniques available in the consortium. Moreover, the measurement of the time lag between the start of the permeation experiment with a completely unloaded membrane and the breakthrough of the permeate allows equivalent information under the initial transient conditions. Particular care is given to the investigation of the influence of as many parameters as possible, including loading, shape of the adsorption isotherm and temperature as well as the nature (size, composition) and the pretreatment conditions (activation, deterioration) of the zeolite membrane. It is the aim, therefore, of this project to use the zeolite-in-metal composite membranes as model membranes for diffusion studies. The zeolite crystals embedded into the metal matrix are the identical zeolite materials used in the parallel diffusion studies by the other members of the consortium. Provided that the preparation of the composite zeolite membranes as described in project 1 will be successful, we would have the unique possibility to (i) derive diffusion coefficients from stationary and instationary permeation experiments and to (ii) forecast the expected permeance of any industrial zeolite membrane, which will be most probably prepared by direct crystallization of a thin zeolite layer on a mesoporous support.