To make natural gas and biogas suitable for use, the methane has to be separated from the CO2. This involves the use of membranes: filters that stop the methane and let the CO2 pass through. Researchers at KU Leuven (University of Leuven), Belgium, have developed a new membrane that makes the separation process much more effective.
When it comes to extracting natural gas or producing biogas, it's all about the methane. But methane is never found in its pure form. Natural gas, for instance, always contains quite a bit of carbon dioxide (the greenhouse gas CO2), sometimes up to 50 percent.
Natural gas or biogas always needs to be purified before use. First, the methane molecules (in black and white) are separated from the CO2 molecules (in red and black) by means of membranes with tiny pores through which only the CO2 can pass. After the purification process, the methane can be used as fuel, for heating, or for the production of chemicals.
Credit: KU Leuven - Verbeke
To purify the methane - or, in other words, remove the CO2 - the industry often uses membranes. These membranes function as molecular sieves that separate the methane and the CO2. The methane can then be used as a source of energy for heating, for the production of chemicals, or as fuel, while the CO2 can be reused as a building block for renewable fuels and chemicals.
Existing membranes still need to be improved for effective CO2 separations, says Professor Ivo Vankelecom from the KU Leuven Faculty of Bioscience Engineering. "An effective membrane only allows the CO2 to pass through, and as much of it as possible.
The commercially available membranes come with a trade-off between selectivity and permeability: they are either highly selective or highly permeable. Another important problem is the fact that the membranes plasticise if the gas mixture contains too much CO2. This makes them less efficient: almost everything can pass through them, so that the separation of methane and CO2 fails."
The best available membranes consist of a polymeric matrix with a filler in it, for instance a metal-organic framework (MOF). This MOF filler has nanoscale pores. The new study has shown that the characteristics of such a membrane improve significantly with a heat treatment above 160 degrees Celsius during the production process.
"You get more crosslinks in the polymeric matrix: the net densifies, so to speak, and that in itself already improves the membrane performance, because it can no longer plasticise. At these temperatures, the structure of the MOF - the filler - changes, and it becomes more selective. Finally, the high-temperature treatment also improves polymer-filler adhesion: the gas mixture can no longer escape through little holes at the filler-polymer interface." This gives the new membrane the highest selectivity ever reported, while preventing plasticisation when the concentration of CO2 is high. "If you start off with a 50/50 CO2/methane mixture, this membrane gives you 164 times more CO2 than methane after permeation through the membrane," Dr Lik Hong Wee explains. "These are the best results ever reported in scientific literature." This study is a collaboration between KU Leuven (Professor Ivo Vankelecom and Dr Lik Hong Wee from the Faculty of Bioscience Engineering / Centre for Surface Chemistry and Catalysis) and UAntwerp (EMAT unit led by Professor Sara Bals). Project website: http://www.
Professor Ivo Vankelecom
Professor Ivo Vankelecom | EurekAlert!
Predicting a protein's behavior from its appearance
10.12.2019 | Ecole Polytechnique Fédérale de Lausanne
Could dark carbon be hiding the true scale of ocean 'dead zones'?
10.12.2019 | University of Plymouth
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.
Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...
Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction
The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...
Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.
Fibroblasts kit - ready to heal wounds
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
10.12.2019 | Architecture and Construction
10.12.2019 | Information Technology
10.12.2019 | Life Sciences