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A nanoporous material for the purification of natural gas and air on an industrial scale?

CNRS Press Release

Genuine sponges of the infinitely small, nanoporous materials make it possible to selectively capture molecules of gas, vapor or liquid, a phenomenon that is of major interest in many industrial processes. A French-Korean consortium comprising researchers from the Institut Charles Gerhardt Montpellier (CNRS / Montpellier University / ENSCM), the Paris Institute of Pore Materials (CNRS / ENS / ESPCI) and the Catalysis and Spectrochemistry Laboratory (CNRS / Normandie University / ENSICAEN) has identified a crystallized porous hybrid material which, once dehydrated, is able to purify natural gas and air by selectively fixing nitrogen gas in the presence of methane or oxygen. Published in the journal Nature Materials, this work makes it possible to envisage more efficient industrial processes of gas separation.

 

The capture of carbon dioxide in the ambient air, the storage of hydrogen or the encapsulation of drugs … As many applications of major industrial interest that can use nanoporous materials …. These materials can indeed use the large surface deployed in their microscopic cavities to capture large quantities of molecules at specific sites.

A Franco-Korean consortium has identified a crystallized porous hybrid material, commonly known as the Metal-Organic Framework (MOF), capable of preferentially fixing nitrogen gas in the presence of methane or oxygen. These molecular simulations were used to guide the choice of the nature of the metal for the selective fixation of nitrogen. The MOF thus formed consists of small Cr (III) metallic units associated with carboxylate ligands which form large cage networks (more than 20 Angstroms). The gaseous molecules of nitrogen can thus penetrate inside and be fixed on the metal centers while remaining stable.

Measurements of adsorption carried out under flow have then demonstrated that this solid exhibits exceptional performances for the selective adsorption of nitrogen in the presence of methane or oxygen and molecular simulations have succeeded in describing its origin by confirming the Role of the interaction between nitrogen and Cr (III) atoms.

These results made it possible to identify for the first time an easily recyclable material capable of purifying natural gas (notably consisting mainly of methane, but in the presence of high concentrations of nitrogen) without using the processes commonly used such as cryogenics, More energy-intensive. No porous solid had so far been able to carry out this type of separation by trapping the nitrogen molecules by interactions with the atoms of the pore. The same material also exhibits better performance than commercially available adsorbents for purification of air with increased purity and adsorbed amounts of nitrogen more than twice as high. This work opens new perspectives on the industrial scale for gas separation.

Numerical simulation of the distribution of nitrogen and methane molecules in MOF cages

Reference

Ji Woong Yoon, Hyunju Chang, Seung-Joon Lee, Young Kyu Hwang, Do-Young Hong, Su-Kyung Lee, Ji Sun Lee, Seunghun Jang, Tae-Ung Yoon, Kijeong Kwac, Yousung Jung, Renjith S. Pillai, Florian Faucher, Alexandre Vimont, Marco Daturi, Gérard Férey, Christian Serre, Guillaume Maurin, Youn-Sang Bae & Jong-San Chang

Selective nitrogen capture by porous hybrid materials containing accessible transition metal ion sites

Nature Materials 19 Décembre 2016
DOI: 10.1038/NMAT4825

Research contact

Guillaume Maurin, Charles Gerhardt Institute Montpellier

Guillaume.Maurin@univ-montp2.fr

At the LCS:

Marco.daturi@ensicaen.fr, alexandre.vimont@ensicaen.fr

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