Capture of CO 2 from flue gas via multiwalled carbon nanotubes

Abstract

Carbon nanotubes (CNTs) were modified by 3-aminopropyl-triethoxysilane (APTS) solution and were tested for its CO 2 adsorption potential at multiple temperatures (20–100 °C). The physicochemical properties of CNTs were changed after the modification, which makes CNTs adsorb more CO 2 gases. The adsorption capacities of CO 2 via CNTs and CNTs(APTS) decreased with temperature indicating the exothermic nature of adsorption process and increased with water content in air at 0–7%. The mechanism of CO 2 adsorption on CNTs and CNTs(APTS) appears mainly attributable to physical force regardless of temperature change, which makes regeneration of spent CNTs at a relatively low temperature become feasible. The CNTs(APTS) have good adsorption performance of CO 2 at 20 °C as compared to many types of modified carbon or silica adsorbents documented in the literature. This suggests that the CNTs(APTS) are promising low-temperature adsorbents for CO 2 capture from flue gas.