A Computational Study on Carbon Dioxide Storage in Single Walled Carbon Nanotubes

Abstract

Carbon nanotubes (CNTs) possess unique electronic, mechanical, and structural properties. They were shown to be effective and stable low temperature adsorbent materials that could make them potentially useful for gas storage and separation of various gas mixtures. Carbon dioxide (CO 2 is a greenhouse gas and CO 2 levels in the atmosphere have been steadily increasing due to human activity. Hence, capturing CO 2 is an active research area. Previous studies on CO 2 adsorption using CNTs focused on low concentration CO 2 environments; however, capturing CO 2 at the source (coal plants, automobile emissions, etc.) is a more realistic solution, therefore, in the current study, the potential use of CNTs as CO 2 adsorbents at high concentration CO 2 environments is reported. The effects of single walled carbon nanotube diameter and length, and CO 2 concentration were studied using molecular dynamics simulations at 300 and 320 K. Results showed that CO 2 molecules were selectively adsorbed by the single walled carbon nanotubes (SWNTs), and adsorption was dependent on both the internal volume of the nanotube and the cross-sectional area of the tube entrance. Temperature increase had a substantial impact on the location of CO 2 molecules in and around the nanotube, i.e., at 300 K, CO 2 molecules were located both inside and on the nanotube surface; whereas at 320 K, the CO 2 molecules were mostly inside the nanotube. This result suggests that the mechanism of CO 2 adsorption and retention can be controlled by temperature. Finally, our results showed that although the amount of adsorbed CO 2 increased with increasing CO 2 concentration, the efficiency of adsorption increased with decreasing CO 2 concentration.

Atomistic molecular dynamics simulations reveal insights into adsorption, packing, and fluxes of molecules with carbon nanotubes

“…The effect of length and diameter are not similar, increasing the diameter of the tube and consequently its cross-sectional area allows an easier access to CO 2 molecules and enables a better packaging of the molecules inside the tube. 35 The adsorption isotherm consists of two phases, a linear and an asymptotic one. The latter corresponds to the beginning of the saturation process.…”

Impact of Impure Gas on CO2 Capture from Flue Gas Using Carbon Nanotubes: A Molecular Simulation Study

“…Among the separation techniques, adsorption separation [ 2 ] is regarded as a promising solution for its low cost and high efficiency. In this connection, a host of conventional and emerging nanoporous materials have been invented and explored, including zeolites, activated carbons, metal-organic frameworks (MOFs), and carbon nanotubes (CNTs) [ 3 , 4 , 5 , 6 , 7 , 8 ]. Particularly, CNTs possess large specific surface areas (greater than 1000 m 2 /g) with strong adsorptive affinities, which could be paired with the superior transport properties to further facilitate the adsorption potentials of [ 3 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] CNTs for CO 2 capture.…”

Bending Solutions of Cantilever Carbon Nanotubes and Molecular Dynamics Simulation

“…4 Due to their superior mechanical, electrical and chemical properties relative to any other known materials, CNTs are being considered as the ideal reinforcing material for the next generation of composites. [5][6][7][8] The applications of CNTs are based on understanding on their mechanical properties and bending problem of cantilever CNTs is the basic problem. As experiments at nano-level are very difficult to control and theoretical atomistic models are computationally intensive for relatively large scale nanostructures, the development and application of continuum mechanics in investigating the bending behaviors of CNTs are of great significance in studying their mechanical behaviors.…”