Adsorption, desorption, and thermodynamic studies of CO2 with high-amine-loaded multiwalled carbon nanotubes

Commercially available multiwalled carbon nanotubes (CNTs) were functionalized with a high mass load of 3-aminopropyltriethoxysilane (APTS) to study their behaviors in the cyclic CO(2) adsorption as well as the associated thermodynamic properties. The breakthrough curve showed a fast kinetics of CO(2) adsorption resulting in percentage ratios of working capacity to equilibrium capacity greater than 80%. The adsorption capacity of CNT(APTS) was significantly influenced by the presence of water vapor and reached a maximum of 2.45 mmol/g at a water vapor of 2.2%. The adsorption capacities and the physicochemical properties of CNT(APTS) were preserved through 100 adsorption-desorption cycles displaying the stability of CNT(APTS) during a prolonged cyclic operation. The heat input required to regenerate spent CNT(APTS) was determined, and the result suggests that adsorption process with solid CNT(APTS) is possibly a promising CO(2) capture technology.