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Study of the separation properties of FAU membranes constituted by hierarchically assembled nanozeolites

 
: Mastropietro, Teresa F.; Brunetti, Adele; Zito, Pasquale F.; Poerio, Teresa; Richter, Hannes; Weyd, Marcus; Wöhner, Steffen; Drioli, Enrico; Barbieri, Guiseppe

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Separation and purification technology 156 (2015), Pt.2, pp.321-327
ISSN: 1383-5866
European Commission EC
FP7-NMP; 262840; DEMCAMER
Design and Manufacturing of Catalytic Membrane Reactors by developing new nano-architectured catalytic and selective membrane materials
English
Journal Article
Fraunhofer IKTS ()
Hermsdorf 2015; nanozeolites; Zeolite membranes; separation properties; water separation

Abstract
In this study, a modified procedure allowing for an easy synthesis of FAU membranes constituted by closely packed nanocrystals and the study of their permeation properties are reported. The FAU layers (Si/Al ratio of ca. 2.5) have a thickness of ca. 20 μm and are constituted by closely packed, well inter-grown nanocrystals, whose dimension was ca. 20–30 nm. The permeation properties of these membranes were measured by feeding H2 and CO2 pure gas. If compared to literature data, a relatively high H2 permeance of ca. 1.4 μmol m−2 s−1 Pa−1 (4177.4 GPU) was measured at 25 °C in dry conditions, which can be attributed to the wide pores of the FAU zeolite and, most likely, to the presence of a secondary mesopore network. The ideal H2/CO2 selectivity was near the corresponding Knudsen coefficient over the entire temperature range investigated (25–75 °C). Furthermore, the potential of these nanozeolite-based membranes for the removal of water vapours from gas mixtures was evaluated by feeding a H2O/N2 mixture, which was used as model system for mimicking a mixture of polar and non-polar components. The water permeation values at 200 °C were ca. 39.9 (M1) and 31.9 (M2) μmol m−2 s−1 Pa−1 (119056.5 and 95185.5 GPU, respectively) at the steady state, with H2O/N2 separation factors of ca. 8 and 7, respectively.

: http://publica.fraunhofer.de/documents/N-374320.html