Carbon Nanotubes Membrane

Since lijima identified carbon nanotubes (CNTs) in 1991, CNTs have been investigated in various fields and become extremely desirable for a wide range of applications. CNTs, with diameters in nanometer scale and a smooth surface may offer a very unique molecular transport through their pores. In fact, several studies in recent years suggest that the water transport through single-walled carbon nanotubes (SWNT) would become much faster than the transport rate that the continuum hydrodynamic theory would predict. This was attributed by Molecular Dynamic (MD) simulation to the smoothness of the nano-tube wall [1,2]. 

Recently Holt et al. [3] developed CNT membranes whose pore sizes were smaller than 2 nm by using a microelectro-mechanical system (MEMS)-compatible fabrication process. 

vertically aligned double-walled carbon nanotubes (DWNTs) were grown on the surface of a sihcon tip by catalytic chemical vapor deposition (Step 

3 in Fig. 8.1a, b). It was followed by conformal encapsulation of the nanotubes by a hard, low pressure chemical vapour deposited silicon nitride (SigN matrix (Sep 

Ismail et at. Carbon-based Membranes for Separation Processes, 

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MiUer, S.A., Young, V.Y., Martin, C.R. Electroosmotic flow in template-prepared carbon nanotube membranes. J. Am. Chem. Soc. 123, 12335-12342, 2001. 

Li, X., Zhu, G., Dordick, J.S., Ajayan, P.M. Compression-modulated tunable-pore carbon-nanotube membrane filters. Small 3, 595-599, 2007. 

To surpass Robeson s upper bound, materials are emerging that rely on transport mechanisms other than solution-diffusion through glassy or rubbery polymeric materials. In particular, a number of materials have been developed that possess fixed microporosity (2 nm or less) in contrast to the activated, transient molecular gaps that give rise to diffusion in most polymers. These materials include amorphous and crystalline (zeolite) ceramics [68-69], molecular sieve carbons [70], polymers that possess intrinsic microporosity [71-72], and carbon nanotube membranes [73-76]. Transport in such materials is determined primarily by the average size and size distribution of the microporosity - the porosity can be tuned to allow discrimination between species that differ by less than one Angstrom in size. However, surface... 

B.J. Hinds, N. Chopra, T. Rantell, R. Andrews, V. Gavalas, and L.G. Bachas, Aligned Multiwalled Carbon Nanotube Membranes, Science, 303 (2004) 62-65. 

Kaha A, Garde S, Hummer G (2003) Osmotic water transport through carbon nanotube membranes. Proc Nad Acad Sci U S A 100 10175-10180... 

Nanofluidics in Carbon Nanotubes, Fig. 1 Sub-2-nm carbon nanotube membrane chip, from Holt et al. [16]... 

Hinds BJ, ChopraN, Rantell T, Andrews R, Gavalas V, Bachas LG (2004) Ahgned multiwalled carbon nanotube membranes. Science 303(5654) 62-65... 

Figure 5.2 Porous structure within various types of membranes [3,22,37], Microporous glass figure from [22], reprinted with permission of John Wiley Sons, Inc. Silica figure from [3], reprinted with permission of Wiley-VCH Verlag GmbH Co. KCaA. Carbon nanotubes figure reprinted with permission from Science, Aligned multiwalled carbon nanotube membranes, by B. ]. Hinds, N. Chopra, T. Rantell, R. Andrews, V. Gavalas and L. C. Bachas, 303, 62-65. Copyright (2004) American Association for the Advemcement of Science.

Hinds, B.J., Chopra, N Rantell, T., Andrews, R Gavalas, V., and Bachas, L.G. (2004) Aligned multiwalled carbon nanotube membranes. Science, 303, 62-65. 

Tong, H. D. Jansen, H. V. Gadgil, V. J. Bostan, C. G. Berenschot, E. van Rijn, C. J. M. Elwenspoek, M. Silicon nitride nanosieve membrane. Nano Lett. 2004,4, 283-287. Sun, L. Crooks, R. M. Single carbon nanotube membranes a well-defined model for studying mass transport through nanoporous materials. J. Am. Chem. Soc. 2000, 122, 12340-12345. 

Das R, Ali ME, Hamid SBA, Ramakrishna S, Chowdhury ZZ. Carbon nanotube membranes for water purification a bright future in water desalination. Desalination 2014 336 97-109. 

Majumder M, Chopra N, Hinds BJ. Mass transport through carbon nanotube membranes in three different regimes ionic diffusion and gas and liquid flow. ACS Nano 2011 5 3867-77. 

Matranga C, Bockrath B, Chopra N, Hinds BJ, Andrews R. Raman spectroscopic investigation of gas interactions with an aligned multiwalled carbon nanotube membrane. Langmuir 2006 22 1235-40. 

Hevia S, Homm P, Cortes A, Nunez V, Contreras C, Vera J, Segura R. Selective growth of palladium and titanium dioxide nanostructures inside carbon nanotube membranes. Nanoscale Res Lett 2012 7 348. 342. 

Yu, M., et al. (2008). High Density, Vertically-Aligned Carbon Nanotube Membranes. Nano letters, 9(1), 225-229. 

Pilatos, G., Vermisoglou, E. C., Romanos, G. E., Karanikolos, G. N., Boukos, N., Eikodimos, V., and Kanellopoulos, N. K. (2010). A closer look inside nanotubes Pore structure evaluation of anodized alumina templated carbon nanotube membranes through adsorption and permeability studies. Adv. Fimt. Mater. 20(15), 2500-2510. 

Amirilargani M, Ghadimi A, Tofighy MA, Mohammadi T (2013) Effects of polyfallylamine hydrochloride) as a new functionalization agent for preparation of poly vinyl alcohol/ multiwalled carbon nanotubes membranes. J Membr Sci 447 315-324 Andrews R, Weisenberger MC (2004) Carbon nanotube polymer composites. Curr Opin Solid... 

Srivastava, A., S. Siivastava, K. Kalaga, Carbon Nanotube Membrane Filters, in Springer Handbook of Nanomaterials. 2013, Springer. 1099-1116. 

K. Falk, F. Sedlmeier, L. Joly, R. R. Netz, and L. r. Bocquet, Molecular origin of fast water transport in carbon nanotube membranes superlubricity versus curvature dependent friction. Nano Lett, 10, 4067 [2010],... 

Membrane filtration is an important technology for ensuring the purity, safety and/or efiticiency of the treatment of water or effluents. In this study, various types of membranes are reviewed, first. After that, the states of the computational methods are applied to membranes processes. Many studies have foeused on the best ways of using a particular membrane process. But, the design of new membrane systems requires a considerable amoimt of proeess development as well as robust methods. Monte Carlo and molecular dynamics methods ean specially provide a lot of interesting information for the development of polymer/carbon nanotube membrane processes. 

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