Regioselective competitive adsorption of water and organic vapor mixtures on pristine single-walled carbon nanotube bundles

Sandeep Agnihotri, Pyoung Chung Kim, Yijing Zheng, José Paulo Barbosa Mota

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Sequential adsorption of water and organic vapor mixtures onto single-walled carbon nanotube (SWNT) bundles is studied experimentally and by grand canonical Monte Carlo (GCMC) simulation to elucidate the distinct interactions between select adsorbates and the nanoporous structure of SWNTs. Experimental adsorption isotherms on SWNT bundles for hexane, methyl ethyl ketone, cyclohexane, and toluene individually mixed in carrier gases that were nearly saturated with water vapor are compared with the GCMC-simulated isotherms for hexane, as a representative organic, on the external surface of the heterogeneous SWNT bundles. From the nearly perfect overlap between the experimental and simulated isotherms, it is concluded that until near saturation only the internal pore volume of pristine SWNT bundles fills with water. The adsorption of water vapor on the peripheral surface of the bundles remains insignificant, if not negligible, in comparison to the adsorption of water in the internal volume of the bundles. This is in contrast with the adsorption of pure hexane, which exhibits appreciable adsorption both inside the bundles and on their external surface. It is also suggested that during competitive adsorption, water molecules take precedence over small nonpolar and polar organic molecules for adsorption inside SWNTs and leave unoccupied the hydrophobic external surface of the bundles for other more compatible adsorbates.
Original languageEnglish
Pages (from-to)5746-5754
Number of pages9
JournalLangmuir
Volume24
Issue number11
DOIs
Publication statusPublished - 3 Jun 2008

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