Designing cellulose based biochars for CO2 separation using molecular simulations

B Barzegar and F Feyzi, SCIENTIFIC REPORTS, 15, 1643 (2025).

DOI: 10.1038/s41598-025-86254-x

This study investigates the pyrolysis mechanism of cellulose using reactive molecular dynamics simulations to prepare biochars for CO2 separation applications. Six biochars with densities ranging from 0.160 to 0.987 g/cm(3) were prepared, and their performance in adsorbing CO2, CH4, and N-2 gases, as well as CO2/CH4 and CO2/N-2 gas mixtures, was evaluated using Grand Canonical Monte Carlo (GCMC) simulations. The adsorption isotherms were fitted to the Dual-Site Langmuir (DSL) equation, and subsequently, the isosteric heat of adsorption, Gibbs free energy, and entropy changes were calculated. It was found that the results indicated that the density of biochar had a strong impact on gabs adsorption. CO2 had much better interactions with biochars than CH4 and N-2. The 0.351 g/cm(3)-density biochar presented the highest selectivity for CO2. The effect of water vapor was also covered which remarkably decreased the adsorption of CO2 by the competition of active sites for adsorption. These results indicate that optimized cellulose- derived biochars could be a promising material for CO2 separation in sustainable gas purification technologies.

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