3 resultados para Microstructure characterization

em University of Queensland eSpace - Australia


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The microstructure of a carbon molecular sieve membrane (CMSM) is characterized using adsorption equilibrium information. The pore size distributions of the CMSM derived from N-2 and CH4 adsorption isotherm are found to be consistent with each other and in agreement with the results of gas permeation experiments as well as the general characteristics of such molecular sieve materials. (C) 2003 Elsevier B.V. All rights reserved.

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In this paper, we present results of the internal structure (pore size and pore wall thickness distributions) of a series of activated carbon fibers with different degrees of burn-off, determined from interpretation of argon adsorption data at 87 K using infinite and finite wall thickness models. The latter approach has recently been developed in our laboratory. The results show that while the low bun-off samples have nearly uniform pore size (

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The microstructural variation of Norit RI Extra activated carbon, progressively heated at 1373 K, was explored in terms of pore size and pore wall thickness distributions, for various periods of heating time, determined by argon adsorption at 87 K, both using an infinite as well as and finite wall thickness model. The latter approach has recently been developed in our laboratory and has been applied to several virgin carbons. The current results show significant variations in small pore size regions (< 7 angstrom) in association with strong growth of thick walls having at least three carbon sheets, as a result of heat treatment. In particular, shrinkage of the smallest pores due to strong interaction between their opposite walls as well as smoothening of carbon wall surfaces due to an increase in graphitization degree under thermal treatment have been found. Further, the results of pore wall thickness distribution are well corroborated by X-ray diffraction. The results of pore size and pore wall thickness distributions are also shown to be consistent with transmission electron microscopy analyses. (c) 2005 Elsevier Ltd. All rights reserved.