STUDY OF THE EFFECT OF FUNCTIONALIZATION OF CARBON NANOTUBES ON GAS SEPARATION

Abstract In order to improve the adsorption capacity and selectivity of CO2/CH4 and CO2/N2, we have functionalized multi-walled carbon nanotubes (MWCNT) with 3-aminopropyltriethoxysilane (APTES). The functionalized MWCNT was characterized by Fourier transform infrared (FT-IR), energy dispersive X-ray spectroscopy (EDX) and BET analysis. CO2, CH4 and N2 adsorption at two different temperatures and P < 5 bar on the functionalized MWCNTs was investigated by the volumetric method. The selectivity of the functionalized MWCNTs for CO2/CH4 and CO2/N2 was studied and compared with MWCNTs. The functionalized MWCNTs show higher adsorption capacity of CO2 and selectivity of CO2/CH4 and CO2/N2 in comparison with the MWCNTs at different pressures. The highest CO2/CH4 and CO2/N2 selectivities for the functionalized MWCNTs were 6.78 and 26.14, respectively, at a pressure of 0.2 bar and at 298 K. Two of the most common adsorption models, the Langmuir and Sips isotherms, were used to correlate the experimental data of CO2 and CH4 adsorption on the adsorbents. The results confirm that the functionalized MWCNTs are promising materials for the separation and purification of gases.