Adsorption and diffusion of carbon dioxide and nitrogen through single-walled carbon nanotube membranes

Abstract

We have used atomically detailed simulations to examine the adsorption and transport diffusion of CO2 and N2 in single-walled carbon nanotubes at room temperature as a function of nanotube diameter. Linear and spherical models for CO2 are compared, showing that representing this species as spherical has only a slight impact in the computed diffusion coefficients. Our results support previous predictions that transport diffusivities of molecules inside carbon nanotubes are extremely rapid when compared with other porous materials. By examining carbon nanotubes as large as the (40,40) nanotube, we are able to compare the transport rates predicted by our calculations with recent experimental measurements. The predicted transport rates are in reasonable agreement with experimental observations.

The Separation Power of Nanotubes in Membranes: A Review

“…Chen and Sholl [156] made atomic calculations to predict the separation between CO 2 and H 2 for SWCNTs and found a remarkable selectivity for CH 4 . Similar results were obtained for carbon dioxide-nitrogen separation [157]. Oxygen to nitrogen selectivity was further described by Arora and Sandler [158] by using molecular dynamics and grand canonical Monte Carlo simulations; this opened the way for air separations.…”

A novel algorithm to model the influence of host lattice flexibility in molecular dynamics simulations: Loading dependence of self-diffusion in carbon nanotubes

“…Furthermore, in the low loading region a plateau region that was not detected when simulating a rigid CNT was observed. In their recent publications Sholl and co-workers [20][21][22][23] investigated the behavior of guest molecules over a wide range of loadings ͑down to the zero loading limit͒. They justified the rigid CNT assumption based on the work of Sokhan et al 16 Indeed Sokhan et al showed that nanotube flexibility plays only a minor role.…”

“…50,68 It is observed that self-and transport diffusivities in CNTs are different by orders of magnitude. 10,23 So it could be that the TDS algorithm has less influence on transport diffusion than on self-diffusion. For instance, it was shown that velocity scaling has no influence on gas effusion from slit pores, compared to a flexible pore model.…”

“…This is a widely made assumption. 10,[17][18][19][20][21][22][23][24][25][26][27] In none of the above mentioned works was the influence of CNT flexibility investigated systematically. Only for a few specific systems was it checked if flexibility had an influence.…”

Flue gas adsorption by single-wall carbon nanotubes: A Monte Carlo study

“…20,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] Most of these simulation studies consider classical force fields, but ab initio calculations have also been reported. 19,27,42 The capacity of carbon nanotubes to adsorb pure CO 2 has been tested by computer simulations in isolated 19 and arrays of parallel SWCNTs, 20 as well as isolated 36 and parallel double-walled carbon nanotube bundles.…”