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A new sulfur containing hydroxy sodalite (S–SOD) of high thermal and hydrothermal stability was synthesized and characterized. XRD measurements showed some differences to normal hydroxy sodalite (H–SOD). But the S–SOD is also quite different from natural sulfur containing sodalites like ultramarine blue. IR– and RAMAN-spectroscopy measurements detected no sulfur radicals in the structure of S–SOD, which was already assumed because of the colorless powder of S–SOD. 29 Si–, 27 Al– and 23 Na–MAS–NMR measurements were conducted to determine the order of the structure and the type of incorporation of the sulfur into the sodalite structure. The sulfur is most likely coordinated statistically on every possible oxygen position in the structure. The pore size of the S–SOD was determined by positron annihilation measurements and is suitable for hydrogen separations. [ABSTRACT FROM AUTHOR]

Micro- and mesoporous alumina membranes attract considerable attention in research and industry for wide variety of applications. Electrochemical oxidation of aluminum followed by detachment of the oxide layer is basically considered well suited for the fabrication of micro- and mesoporous alumina membranes. However, common preparation routes include complex work steps, harsh chemicals, excessive rate of material consumption and are limited in scalability, leading to high cost and rare application. Herein, a facile route for the fabrication of nanostructured alumina membranes based on a series of electrochemical process steps is described. The process chain is outlined along representative results and corresponding materials characterization of the resulting alumina membranes. The flexibility of the production route with regard to decisive membrane properties and possible post-treatment steps is demonstrated by way of example. The main advantages in comparison with common processes for the fabrication of micro- and mesoporous alumina membranes are discussed. The described process chain appears promising for both, facile lab scale preparation of tailor-made alumina membranes and large scale fabrication for a wide variety of applications. Image 1 • Straightforward semi-continuous preparation of nanostructured alumina membranes. • Versatile pore designs by current/voltage modulated anodizing regimes. • Semi-continuous process management renders cumbersome pretreatment steps unnecessary. • Near-net-shape production avoids costly post treatment. • Versatile tool box for lab-scale preparation of alumina membranes. [ABSTRACT FROM AUTHOR]