Molecular modelling to push the limit of CO2 separation

Many environmental challenges of modern society are related to sustainable energy consumption. In particular, the need to reduce the atmospheric CO2 emissions from the combustion of fossil fuels is one of the main driving forces pushing research to find alternative and effective solutions not only to reduce the emissions, but also to separate and capture the emitted CO2. Membrane technology has become very competitive, much more than the traditional separation methods, such as adsorption, cryogenic separations, distillation, etc., since offers improved performance at lower cost with increased energy efficiency and lower environmental impact [1-3]. The successful development of highly permeable and selective membranes makes a membrane-based process a viable alternative for carbon dioxide capture and storage from flue gas. The classical simulation study at molecular level by using molecular dynamic simulations (MD) can powerfully support experimental studies about morphological and transport behaviour of such systems [4,5]. In the present work MD method has been applied for a detailed investigation of gas molecules transport through TRPBO membranes both in single gas state (CO2 and N2) and in binary gas mixture (CO2:N2) at high trans-membrane pressure difference (5 bar). The results revealed that the CO2 permeability under the mixed-gas condition remained the same as the single gas, while the permeability of other gas decreased, thus leading to a favored increase in selectivity. The theoretical data, along with the experimental results [6], give further information about the microscopic structure and atomistic interactions between gases, thus resulting in a reciprocal validation and useful correlations between MD and experimental analysis.