The greatest threat of the 21 st century is Global Warming, and its causes are deforestation, intensive farming, exploitation of fossil fuels, waste disposal, mining, etc. Moreover, global warming has drastic effects on biodiversity, oceans, weather, and humans. As Greenhouse gases accelerate the process of global warming, the reduction of its level is the need of the hour.
We are the first generation to feel the sting of climate change and we are the last generation that can do something about it.
Jay Inslee
In 2019, the European Commission presented the “Green Deal”. This emphasized the reduction of Greenhouse gases to zero level by 2050 within the European Union(EU).
Chemists at the University of Bayreuth, Germany came up with a new Inorganic-Organic hybrid material recently. This material specifically separates Carbon Dioxide, which is one of the major Greenhouse gases, from natural gas and industrial waste gas. This is actually an important step for climate protection and sustainable industrial production. The adsorbed CO2 can later be used as a resource for the industrial process.
What is this novel hybrid material?
Physisorbent is a substance that can form weak bonds with certain molecules. Like charcoal which is an adsorbent in treating wastewater from textiles, Diammonium pillared MOPS-7(Microporous Organically Pillared layered Silicate-7) is the selective physisorbent of CO2.
MOPS-7 is received as a microcrystalline product by topotactic (exchange of atoms within crystal lattice) pillaring of fluorohectorite(a clay mineral which is mixed oxide/silicate/fluoride of Lithium and Magnesium) with DAB (1,4-diamino butane dihydrochloride). It is prepared by the simple Ion Exchange of Na-Hec (inexpensive clay) suspended in water with DAB.
Clay minerals are the chemical basis present in MOPS-7 along with 1 nanometre thick hundreds of glass platelets arranged one above the other. Organic molecules present between these glass plates act as spacers. The chemical properties and shape of organic molecules have been set so that the pore space formed is suited only for CO2. For enhancing the CO2 selectivity of the material, the molecular sieve effect is applied. With this effect, gases like Nitrogen, Methane, etc. will remain outside the material because of their molecular size. Due to physical interaction, CO2 gets accumulated into the cavities of the hybrid material.
According to Martin Rieß, M.Sc., first author of this publication and a doctoral researcher at the University of Bayreuth, the research team has accomplished in the making of this material that fulfils two missions at the same time. Firstly, MOPS-7 liberates and holds onto CO2 from a mixture of gases. This is due to the comparatively strong physical interaction of the material with CO2. Secondly, the material is weak enough to permit the release of CO2 with a small amount of energy.
Merits of MOPS-7 over others:
(i) It is an easy to synthesize physisorbent.
(ii) Its shape, polarity, and pore size are specially customized for superior carbon dioxide selectivity thus making it a comparatively strong physisorbent.
(iii) It is energy efficient and economical.
(iv) MOPS-7 can remove CO2 completely from gas mixtures (waste gases, biogas) without chemically binding it.
(v) CO2 can later be released without the need for any high energy.
The Special measuring system in Bayreuth laboratory helps for the precise determination of the amount of gases adsorbed and selectivity of MOPS-7. The hybrid material has fulfilled all the criteria for the evaluation of the industrial CO2 separation procedure.
At present, the research team is working on a membrane system based on clay minerals. This will be designed in such a way that it allows the selective, continuous, and energy-efficient separation of CO2 from other gases. Let’s aim to build a carbon-free Earth for the coming generations.
Source
Read another article on same topic – “Fixation of Carbon dioxide by artificial photosynthesis”
Author
