Pore size characterization

Chiu, C. Y. Chiang, A. S. T. Chao, K. J. 2006. Mesoporous silica powders and films—Pore size characterization by krypton adsorption. Microporous Mesoporous Mater. 91 244-253. 

Two kernels of theoretical isotherms in cylindrical channels have been constructed corresponding to the adsorption and desorption branches. For a series of samples [2-4], we show that the pore size distributions calculated from the experimental desorption branches by means of the desorption kernel satisfactory coincide with those calculated from the experimental adsorption branches by means of the adsorption kernel This provides a convincing argument in favor of using the NLDFT model for pore size characterization of nanoporous materials provided that the adsorption and desorption data are processed consistently,... 

C. Nondestructive Physical Tests for Pore Size Characterization... 

Ravikovitch PI, Vishnyakov A, Russo R, and Neimark AV. Unified approach to pore size characterization of microporous carbonaceous materials from N2, Ar, and C02 adsorption isotherms. Langmuir, 2000 16(5) 2311-2320. 

The problem of adsorption hysteresis remains enigmatic after more than fifty years of active use of adsorption method for pore size characterization in mesoporous solids [1-3]. Which branch of the hysteresis loop, adsorption or desorption, should be used for calculations This problem has two aspects. The first is practical pore size distributions calculated from the adsorption and desorption branches are substantially diflferent, and the users of adsorption instruments want to have clear instructions in which situations this or that branch of the isotherm must be employed. The second is fundamental as for now, no theory exists, which can provide a quantitatively accurate description of capillary condensation hysteresis in nanopores. A better understanding of this phenomenon would shed light on peculiarities of phase transitions in confined fluids. 

Rao, M.B. and Sircar, S. Performance and pore size characterization of nano-porous carbon membranes for gas separation. Journal of Membrane Science, 1996, 110, 109. 

P.I. Ravikovitch and A.V. Neimark, Density Functional Theory of Adsorption in Spherical Cavities and Pore Size Characterization of Templated Nanoporous Silicas with Cubic and Three-dimensional Hexagonal Structures, Langmuir, 2002, 18, 1550-1560. 

A consequence of the ill-posed nature of Eq. (14), therefore, is that different PSD results can be obtained for the same material if different methods are applied to solve the adsorption integral equation, even if the same experimental data and adsorption model are used in both cases. A standard protocol has not yet been agreed upon for the use of regularization in pore size characterization. To avoid confusion in comparing PSD results, therefore, the numerical method employed to solve for the PSD and the type of regularization, if any, implemented to smooth the PSD should both be clearly identihed. 

Ravikovitch PI, Neimark AV Density functional theory of adsorption in spherical cavities and pore size characterization of templated nanoporous sihcas with cubic and three-dimensional hexagonal structures, Langmuir 18(5) 1550-1560, 2002. 

Sur ce area and pore size characterizations were performed using a Micromeritics ASAP2000 gas adsorption surface area analyzer. The specific surface area of the samples was determined from the nitrogen isotherms at 77K and by using the BET equation. Micropore volume was determined using the DR equation and the total volume of pores was calculate at a relative pressure (p/p ) of 0.97. Table 1 shows the activation conditions and the structural characterization. More details are given elsewhere [3]. 

Tu, S.K., Bhatia, S.K., Mlynarek, J., 2002. Standardization of the bubble point method for the pore size characterization of woven and nonwoven geotextiles. In Proc. 7th ICG, 1111-1114. 

Ramaswamy, S., Greenberg, A. R., and Peterson, M. L. (2004). Non-invasive measurement of membrane morphology via UFDR Pore-size characterization. J. Membr. Sci. 239, 143. 

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