Carbon molecular sieve characterization

Cazorla-Amoros D, Alcaniz-Monge J, Casa-Lillo MA, and Linares-Solano A. C02 as an adsorptive to characterize carbon molecular sieves and activated carbons. Langmuir, 1998 14(16) 4589-4596. 

Two kinetic (CMS-Kl, CMS-K2) and one equilibrium (CMS-R) carbon molecular sieves, used originally for separation of gaseous mixtures, were investigated. The adsorption Nj isotherms at 77 K, in static conditions where obtained. In the case of the two first sieves the adsorption was so low that the calculation of parameters characterizing the texture was impossible. The volume of nitrogen adsorbed on the sieve CMS-R is remarkable From obtained results parameters characterizing micropore structure according to Dubinin -Radushkevich equation and Horvath - Kawazoe method were determined. 

Such result is consistent with the literature [1]. In this way it was found that the measurements based on displacement of fluids with different molecular sizes enable characterization of the micropore structure of carbon molecular sieves. However for CMS- R sieves a some amount of micropores with the size of 0.255 -s- 0.528 nm was found, but its volume is smaller than in the case of CMSs-K. 

Cazorla-Amoros D., Alcaniz-Monge J., De la Casa-Lillo M. A. and Linares-Solano A. CO2 As an Adsorptive to Characterize Carbon Molecular Sieves and Activated Carbons, Langmuir 14 (1998) pp.4589-4596. 

Jones C.W. and Koros W.J., Carbon molecular sieve gas separation membranes—I. Preparation and characterization based on polyimide precursors. Carbon 52 1419 (1994). 

In the present work, AlMCM-41 materials with different nsi/n,y-ratios were used as support for copper and zinc species, which were introduced during the synthesis of the mesoporous molecular sieve. Characterization of the metal-containing materials was primarily achieved by carbon monoxide adsorption and temperature programmed reduction In particular the aim of this work was to distinguish between isolated copper species grafted on the wall of MCM-41 and/or or the formation of copper oxide clusters located in the channels... 

Since carbon molecular sieves are amorphous materials, the dimensions of their pore structures must be measured phenomenologically by the adsorption of small probe molecules with different critical dimensions. There is insufficient long range order to utilize standard x-Ray diffraction methods for characterization. The earliest reports of molecular sieving carbons dealt primarily with coals and charcoals. Sorption of helium, water, methanol, n-hexane, and benzene was measured and related to the porosity of the carbon. Pore-sizes were estimated to be two to six angstroms (3-6). In a classic paper P.H. Emmett described methods for tailoring the adsorptive properties and pore size distributions of carbon Whetlerites. 

Characterization of IOM-CMS Materials by Molecular Probe Adsorption. Since carbon molecular sieves, and the IOM-CMS materials prepared herein, are both polycrystalline and amorphous, we have characterized their sieving properties phenomenologically by molecular probe adsorption. The probe... 

Krutyeva et al. (2009) used combined NMR cryoporometry, relaxometry, and diffusometry to characterize porous carbon materials. They studied two carbon molecular sieves (CMS Takeda 4A... 

Darmstadt et al. characterized mesoporous carbon molecular sieves obtained by pyrolysis of sucrose in SBA-15 (CMK-3F series) and MCM-48 (CMK-IF series) silica matrices by adsorption of nitrogen at 77 K and observed that on head treatment up to 1600°C, the CMS obtained were associated with only mesoporous, almost all of the micropores were converted into mesopores (Figure 4.5a,b). 

This book has been written in eight chapters, which cover activated carbons their surface structure the adsorption on solid surfaces and the models of adsorption adsorption from solution phase the preparation, characterization of, and adsorption by carbon molecular sieves important applications of activated carbons with special emphasis on medicinal and health applications and the use of activated carbons in environmental clean up. 

Production, characterization and applications of carbon molecular sieves from a high ash Greek lignite... 

The purpose of this paper is to present such a model which can be regarded as a synthesis of fundamental considerations resulting from the activities in porous sorbents characterization and classical thermodynamics developments. This model is able to represent in a correct way adsorption data of oxygen, argon, nitrogen and methane on a given carbonaceous adsorbent using a unique pore size distribution function whatever the adsorbate. The procedure was applied on four different activated carbons and on a carbon molecular sieve. The adsorption isotherms were measured at 283 K, 303 K and 323 K and for pressures up to 2200 kPa. 

Activated carbons are widely used as adsorbents in either the gas or the liquid phase, and also as catalysts and catalyst support. In some cases their adsorption behaviour depends basically on their textural characteristics, i.e., porous structure and pore volume. As an example carbon molecular sieves (CMS) are a kind of activated carbons that make use of a narrow pore size distribution, of a few angstroms in diameter, to selectively separate gas mixtures [1], such as N2/O2, CO2/CH4, C3H6/C3H8 and some others. But also the surface chemistry can condition in many cases [2,3] the adsorption behaviour, as well as the activity as catalyst and catalyst support [4, 5]. This means that the adsorption properties of the activated carbons cannot be easily explained only on the basis of textural characteristics (surface area and pore size distribution) the nature of the chemical surface must also be taken into account. Therefore, for a complete characterization of the activated carbon surface, textural and chemical characteristics must be assessed. 

Selvam, P. Kuppan, B. Synthesis, characterization and electrocatalytic properties of nano-platinum-supported mesoporous carbon molecular sieves, Pt/NCCR-41. Catal. Today 198 (2012), pp. 85-91. 

Jones CW, Koros WJ (1994) Carbon molecular sieve gas separation membranes- I. Preparation and characterization based on polyimide precursors. Carbon 32 (8) 1419-1425 Jones CW, Koros WJ (1995) Characterization of ultramicroporous carbon membranes with humidified feeds. Ind Eng Chem Res 34 (1) 158-163... 

Kim YK, Park HB, Lee YM (2005) Preparation and characterization of carbon molecular sieve membranes derived from BTDA-ODA polyimide and their gas separation properties. J Membr Sci 255 (1-2) 265-273... 

Lagorsse S Magalhaes FD, Mendes A (2007) Xenon recycling in an anaesthetic closed-system using carbon molecular sieve membranes. J Membr Sci 301 (1-2) 29-38 Ismail AF, Li K (2008) From polymeric precursors to hollow fiber carbon and ceramic membranes. In Inorganic Membranes Synthesis, Characterization and Applications, Mal-lada R, Menendez M (Eds.) Membrane Science Technology Ser, Elsevier, Amsterdam, The Netherlands, Vol 13, Ch3, 81-119... 

Sedigh MG, Jahangiri M, Liu PKT, Sahimi M, Tsotsis TT (2000) Structural characterization of polyetherimide-based carbon molecular sieve membranes. AIChE J 46 (11) 2245-2255... 

Perry JD (2007) Formation and characterization of hybrid membranes utilizing high-performance polyimides and carbon molecular sieves. PhD thesis, Georgia Institute of Technology, Atlanta, GA, USA... 

Nguyen C, Do DD, Haraya K, Wang K (2003) The structural characterization of carbon molecular sieve membrane (CMSM) via gas adsorption. J Membr Sci 220 (1-2) 177-182 Nguyen C, Do DD (1999) Adsorption of supercritical gases in porous media Determination of micropore size distribution. J Phys Chem B 103 (33) 6900-6908 Katsaros FK, Steriotis TA, Ramanos GE, Konstantakou M, Stubos AK, Kanellopoulos NK (2007) Preparation and characterization of gas selective microporous carbon membranes. Microporous Mesoporous Mater 99 (1-2) 181-189... 

Lagorsse S, Magalhaes FD, Mendes A(2004) Carbon molecular sieve membranes Sorption, kinetic and structural characterization. J Membr Sci 241 (2) 275-287 Lagorsse S, Leite A, Magalhaes FD, Bischofberger N, Rathenow J, Mendes A (2005) Novel carbon molecular honeycomb membrane module Configuration and membrane characterization. Carbon 43 (4) 809-819... 

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