Microtrapping characteristics of single and multi-walled carbon nanotubes

National Center of Excellence for Environmental and Hazardous Waste Management, Chulalongkorn University, Bangkok, Thailand.
Journal of Chromatography A (Impact Factor: 4.26). 04/2008; 1185(2):161-6. DOI: 10.1016/j.chroma.2008.01.073
Source: PubMed

ABSTRACT Carbon nanotubes (CNTs) possess some highly desirable sorbent characteristics, which make them attractive for a variety of applications including micro-scale preconcentration. The main advantage of CNTs is that they are non-porous, thus eliminating the mass transfer resistance related to diffusion into pore structures. Their high aspects ratio leads to large specific capacity, consequently they have the potential to be the next generation high performance sorbent. In this paper we present the microtrapping. The objective of this paper was to study the sorption of select organic compounds on single and multi-walled nanotubes either packed or self-assembled onto a micro-sorbent trap. The data show that the CNTs show highly favorable adsorption as well as desorption. The former is characterized by relatively large breakthrough volumes and isosteric heats of adsorption (DeltaH(s), close to 64 kJ/mol). Similarly, rapid desorption from CNTs was demonstrated by narrow desorption bandwidth. The elimination of non-tubular carbons (NTC) from the CNT surface is important, as they reduce the performance of these sorbents.

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    ABSTRACT: Multiwall carbon nanotubes (MWCNT) network called "Buckypaper" was made by the vacuum filtration method from MWCNT aqueous suspension. In this way we created multi-wall carbon nanotube (MWCNT) networks featured by randomly entangled pure nanotubes. These networks were applied as gas sensors for organic vapors of ethanol and heptane, polar and nonpolar solvents respectively. The gas response was investigated by electrical resistance measurements. The surface sensitivity and selectivity was then modified by low-temperature reactive surface plasma treatment in different gases. With plasma treatment, we first created the functional groups on the nanotubes surface and latter etch them. These processes changed surface selectivity for detection of organic vapors. The results showed that the MWCNT network electrical resistance increased when exposed to organic solvent vapors. This is reversible process, when removed from the vapors. Therefore, the MWCNT networks show the potential to be used as improved sensing elements for sensitive and selective organic vapor detection in near future.
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    Annals of Occupational Hygiene 07/2014; 58(7). DOI:10.1093/annhyg/meu043 · 2.07 Impact Factor
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