Fractal Analysis

Neimark, Alexander V.

doi:10.1002/9783527618286.ch4

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…The fractal dimension of the materials was estimated in an attempt to analyze the complexity of their porous network . For this purpose, the refinement of the Wang and Li method proposed by Sandoval-Díaz et al was applied.…”

Section: Experimental and Analytical Methodsmentioning

confidence: 99%

“…The fractal dimension of the materials was estimated in an attempt to analyze the complexity of their porous network. 74 For this purpose, the refinement of the Wang and Li method 75 proposed by Sandoval-Di ́az et al 76 pore size distribution and fractal dimension, 77,78 making use of the integral Kiselev equation for estimating the excess surface area (or chemical potential) while also applying a standard thickness equation for estimating the pore size. 76 Ultimately, Sandoval-Di ́az et al 76 made the linear fitting of:…”

Section: Assessment Of Porosity Surface Area and Fractal Dimensionmentioning

confidence: 99%

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Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Baldovino-Medrano,

Niño-Celis,

Isaacs Giraldo

2023

J. Chem. Eng. Data

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Amorphous aluminosilicates are applied in adsorption and catalysis because they can be designed to possess micro-, meso-, and macropores. In this work, we analyze the nitrogen physisorption isotherms recorded for a series of materials based on amorphous aluminosilicates synthesized by sol−gel via hydrolysis in acidic medium (ACSG), sol−gel with a poly(ethylene glycol) template (P), and sol−gel with gel skeletal reinforcement (GRS). We found that the porosity of the ACGS and GRS types of materials was dominated by mesopores, while that of the P-type materials was dominated by micropores but with a non-negligible fraction of mesopores. We catalogued the isotherms produced by the latter type of materials as type IV(c) as a supplement to the current IUPAC classification. In addition, we found that the hysteresis loops shown by the amorphous aluminosilicates of the ACGS-type materials present inflection points not found in the current IUPAC classes; therefore, we propose classifying them as H3(b) types. We also assessed the surface area and porosity of the materials by classical methods, namely, the Brunauer−Emmett−Teller (BET) surface area, t-plot microporosity, Barrett−Joyner− Halenda (BJH) mesopore size distribution, and fractal dimension. First, we found a semiexponential correlation between the C BET constant of the materials and their relative fraction of the microporous surface area. Second, we found that under the conditions used herein, the impregnation of a NiMo phase over the synthesized amorphous aluminosilicates increased the C BET constant and reduced the fractal dimension of the materials. These changes were thus correlated to the changes observed in the relative microporosity and mesoporous size distributions of the materials.

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Section: Experimental and Analytical Methodsmentioning

confidence: 99%

Section: Assessment Of Porosity Surface Area and Fractal Dimensionmentioning

confidence: 99%

Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Baldovino-Medrano,

Niño-Celis,

Isaacs Giraldo

2023

J. Chem. Eng. Data

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“…where D f is the fractal dimension and R x is a measure of the agglomerate size, which according to Neimark (2002), is here set equal to the spatial scale of the whole system: the particle size L. The particle density is then proportional to the size of the particle according to…”

Section: Silica Particles Densitymentioning

confidence: 99%

Model development for the description of silica particles dispersion in silicone polymer

Schaer

Guizani

Choplin

2006

Chemical Engineering Science

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Surface Area and Porosity

Neimark

Sing

Thommes³

2008

Handbook of Heterogeneous Catalysis

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147

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The sections in this article are Introduction Physisorption of Gases Determination of Surface Area A The BET Method B The Standard Isotherm Concept Assessment of Porosity A Capillary Condensation and the Kelvin Equation B Adsorption Hysteresis C Microporosity D Micropore Analysis: Dubinin's Theory of Micropore Filling E Micropore Analysis: Empirical Methods F Other Methods for Micropore Pore Size Analysis G Application of Density Functional Theory Adsorption at the Liquid–Solid Interface Adsorption from Solution Heat of Immersion Mercury Porosimetry General Conclusions

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Fractal Analysis

Cited by 4 publications

References 28 publications

Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Systematic Analysis of the Nitrogen Adsorption–Desorption Isotherms Recorded for a Series of Materials Based on Microporous–Mesoporous Amorphous Aluminosilicates Using Classical Methods

Model development for the description of silica particles dispersion in silicone polymer

Surface Area and Porosity

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