Événement

Caro starts with some novel preparation techniques for supported MOF membranes Supported thin MOF layers are usually prepared by solvothermal crystallization. Also counter diffusion and interfacial growth, chemical vapor deposition, electrophoretic nuclei assembly, pseudomorphic replication or phase transformation, and layer-by-layer (l-b-l) techniques by dipping/spraying can be used. Recent developments in gas separation membranes such as switching of gas transport by external stimuli like electric fields [1] or light of a certain wavelength [2] are highlighted.
A new field of membrane research is the deposition of 2D nano-sheets to stacked membranes. Recent examples are synthesis of MXene (Ti3AlC2 )[3,4] and g-C3N4  [5] membranes with synthesis of the nano-sheets from the 3D materials (top down). New COF membranes allow high water flux and good dye/drug retention [6].
Membranes can be used in membrane reactors for process intensification. One example is the formation of dimethylether (DME) from methanol (MeOH) according to 2 MeOH D DME + H2O. The product water was removed through a hydrophilic LTA membrane [7]. A second example is to support the aromatization of methane by using oxygen or proton conducting membranes. Proton conducting ceramics can shift the equilibrium 6 CH4 D C6H6 + 9 H2 by extracting hydrogen [8]. Oxygen transporting membranes can influence the reaction by the in situ combustion of hydrogen 6 CH4 + 4,5 O2 ® C6H6 + 9 H2O [9].
[1] A. Knebel, B. Geppert, K. Volgmann, D.I. Kolokov, A.G. Stepanov, J. Twiefel, P. Heitjans, D. Volkmer, J. Caro, Defibrillation of soft porous metal-organic frameworks with electric fields, Science, 358 (2017) 347.
[2] Z. Wang, A. Knebel, S. Grosejan, D. Wagner, S. Bräse, C. Wöll, J. Caro, L. Heinke, Tunable molecular separation by nanoporous membranes, Nature Commun. 7:13872, 2016.
[3] L. Ding, Y. Wei, L. Li, T. Zhang, H.H. Wang, J. Xue, L.-X. Ding, S. Wang,  J. Caro, Y. Gogotsi, MXene molecular sieving membranes  for highly efficient gas separation, Nature Communications 9 (2018), 155.
[4] L. Ding, Y.Y. Wei, Y. Wang, H.B. Chen, J. Caro, H.H. Wang, A two-dimensional Lamellar Membrane: MXene Nanosheet Stacks, Angew. Chem. Int. Ed. 56 (2017) 1825.
[6] Y. Wang, L. Li…H. Chen, L. Ding, J. Caro, H.H. Wang, Water transport with ultralow friction through partially exfoliated g-C3N4 nanosheet membranes with self-supporting spacers, Angew. Chem. Int. Ed. 56 (2017) 8974.
[6] H. Fan, J. Gu, H. Meng, A. Knebel, J. Caro, High-Flux Membranes Based on the Covalent Organic Framework COF-LZU1 for Selective Dye Separation by Nanofiltration, Angew. Chem. Int. Ed.Int. Ed. 57 (2018) 4083.
[7] J. Xue...A. Feldhoff, H.H. Wang, J. Caro, Gas to liquids: Natural gas conversion to aromatic fuels and chemicals in a hydrogen-permeable ceramic hollow fiber membrane reactor, ACS Catalysis, 6 (2016) 2448-2451.
[8] Z. Cao, H. Jiang, H. Luo, S. Baumann, W.A. Meulenberg, J. Assmann, L. Mleczko, Y. Liu, J. Caro, Natural gas to fuels and chemicals: improved methane aromatization in the oxygen-permeable membrane reactor, Angew. Chem. Int. Ed. 52 (2013) 13794-13797.
[9] C. Zhou, N. Wang, Y. Qian, X. Liu, J. Caro, A. Huang,     Efficient synthesis of dimethyl ether from methanol in a bifunctional zeolite membrane reactor, Angew. Chem. Int. Ed. 55 (2016) 12678-12682.

Lien vers le site web: https://memento.epfl.ch/event/smart-membranes-perovskite-zeolite-mof-cof-mxene-m/

Plus d'informations