Allylamide-grafted multiwall carbon nanotubes as a new type of nanoadsorbent for the H2S removal from gas stream

In the present study, multiwall carbon nanotubes (MWCNTs) were modified to produce novel carbon based material called allylamide-grafted multiwall carbon nanotubes (AGMWCNTs). The Fourier transform infrared spectroscopy characterization of AGMWCNTs demonstrated major peaks indicating functional groups such as O-H/NH, C-H and C=O stretching. Adsorption of H2S by AGMWCNTs was studied under different experimental conditions and the results were compared with those obtained by oxidized MWCNTs (OMWCNTs). Analysis of the effects of contact time and temperature on the H2S adsorption indicated that AGMWCNTs exhibit a higher adsorption capacity than OMWCNTs, which may be attributable to their effective nitrogen functionalities. Moreover, comparison of breakthrough curves describing the time-dependence of H2S output concentrations indicated that the H2S output concentration of AGMWCNTs after 55 min was about 2-fold lower than that of OMWCNTs. Finally, analyses of the equilibrium models used to describe the experimental data showed that the three-parameter isotherm equations Toth and Sips provided slightly better fits compared to the three-parameter isotherms. (C) 2016 Elsevier B.V. All rights reserved.