Optimal Performance of Nanoporous Carbons on Adsorptive Separation of CO2 from Flue Gas

We adopted grand canonical Monte Carlo (GCMC) simulations to comprehensively investigate the adsorption of CO2/N-2 mixtures of different compositions in well-shaped single-walled carbon nanotubes (CNTs), stratified activated carbon fiber (ACF-15), and completely disordered silicon carbide-derived carbon (SiC-DC) at different temperatures. It was found that reducing the pore size initially enhances the adsorption and selectivity of CO2 for enhanced adsorbate-adsorbent interactions, which, however, eventually reduces the selectivity for the enhanced entropic effect. It was also revealed that formation of a cylindrical pore could dramatically enhance the potential field, emphasizing that the morphology of the carbons could have a significant impact on the adsorptive separation performance. While increasing the temperature reduces the separation performance, the enhanced mole fraction of CO2 after multistage separation facilitates the subsequent flue gas separation procedure. A performance coefficient was adopted to comprehensively measure the separation performance of nanoporous carbons on the separation of CO2 from CO2/N-2 mixtures with varying compositions and at different temperatures. Among the CNTs considered, either the (6, 6) or the (7, 7) CNT achieves the best separation performance for specific working conditions, associated with the performance coefficient being around 1 order of magnitude higher than the counterparts of ACF-15 and SiC-DC.

Automated summary

Through investigating the adsorption of CO2/N-2 mixtures in different carbon materials at varying temperatures, it was found that reducing pore size can enhance CO2 adsorption and selectivity, but may reduce selectivity for entropy effects; morphology significantly impacts adsorptive separation performance; increasing CO2 mole fraction can improve separation performance, while increasing temperature decreases it.