The photo is sourced from filtsep.com
Membranes are porous polymer materials used to separate CO2 from the flue gases of thermal power plants (TPPs). They trap atmosphere-safe nitrogen and pass through the carbon dioxide well, the latter is then removed by a cleaning system and placed into tanks, from which it can be extracted for industrial use.
Membranes are usually made of cellulose acetate, a polymer based on an ordinary plant fibre, to which acetic acid residues are attached. The scientists from the Topchiev Institute of Petrochemical Synthesis of the Russian Academy of Sciences have proposed a commercially scalable alternative by replacing the main cellulose chain with a polycycloolefin chain, in which carbon atoms are bound into complex three-dimensional ring structures. Such compounds have high thermal and chemical stability.
The authors of the study introduced ester groups containing carbon and oxygen atoms into the polymer. This increased the material’s ability to bind with carbon dioxide and accelerate the CO2 passing through the membrane. So, in comparison with a cellulose acetate membrane, the new material separated carbon dioxide and nitrogen twice as well, and its permeability to carbon dioxide was more than 60 times higher. Therefore, the new membrane will increase the efficiency of industrial gas separation.
The results of the study turned out to be unexpected for its authors. As a rule, with an increase in membrane permeability, selectivity of gas separation decreases, whereas with an increase in the gas separation quality, permeability decreases. Introduction of ester groups into the polymer led to improvement of both parameters.
“The resulting material has demonstrated the excellent gas separation properties. The new polymer’s structure is simple and easy to obtain – the proposed membranes can be created from petroleum products and traditional acrylic monomers, which makes them affordable. “Their introduction into gas removal systems will help reduce the greenhouse effect caused by the emissions from thermal power plants and other industrial enterprises,” the Institute of Petrochemical Synthesis of the Russian Academy of Sciences quotes Evgenia Bermesheva, PhD in chemical sciences.
