Description of Gas Adsorption Isotherms on Porous and Dispersed Systems with the Excess Surface Work Model

Setzer, Μ.J.

doi:10.1006/jcis.1998.5786

Cited by 38 publications

(18 citation statements)

References 12 publications

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“…There are also several studies on the hysteresis region and attempts to theoretically explain and model isotherms of cellulose and biological materials including the hysteresis [16,20,21]. A very interesting and powerful thermodynamic model has been worked out by Adolphs and Setzer [22][23][24][25]. This model allows for the description of sorption isotherms by a few signi cant numbers.…”

Section: Theorymentioning

confidence: 99%

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A numeric model for the kinetics of water vapor sorption on cellulosic reinforcement fibers

Kohler¹,

Dück²,

Ausperger³

et al. 2003

Composite Interfaces

100

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Some natural bers like ax, hemp and others show excellent mechanical properties that make them a promising choice for the reinforcement of polymers. The increasing research on natural ber reinforced composites has still left important questions open, mainly concerning the ber-matrix interface. Compared to the well optimized glass bers, cellulose bers show very different interaction with matrix polymers and adhesion promoters. The hydrophilic cellulose structure allows for the penetration of a considerable amount of water into the amorphous regions of the bers, eventually exceeding 20% by mass, depending on ber type, preparation and environmental humidity. Even embedded in totally apolar polymers the cellulose partly retains its ability for water sorption, which results in unfavorable effects, such as dimensional changes, decrease in strength, roughening of the surface, etc.The interaction of differently prepared bers with water vapor and the effect of surface treatment is investigated by measuring the dynamics of water vapor sorption. An exponential model is used for the numerical evaluation of the sorption and desorption kinetics. The model not only allows for an excellent t of the experimental isotherms, but without any further assumptions it immediately gives evidence of the existence of two distinct mechanisms for the exchange of water vapor, related to different sorption sites. These speci c mechanisms are represented by individual sorption-desorption isotherms as components of the total isotherms. The model provides a clearer differentiation of the effects of ber preparation and modi cation with respect to interfacial interactions.

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Section: Theorymentioning

confidence: 99%

“…Beside the classical models of Brunauer-Emmet-Teller, De Boer and others there are still new approaches [16][17][18][19][20][21][22][23][24]. There are also several studies on the hysteresis region and attempts to theoretically explain and model isotherms of cellulose and biological materials including the hysteresis [16,20,21].…”

Section: Theorymentioning

confidence: 99%

A numeric model for the kinetics of water vapor sorption on cellulosic reinforcement fibers

Kohler¹,

Dück²,

Ausperger³

et al. 2003

Composite Interfaces

100

View full text Add to dashboard Cite

show abstract

“…1(b), changes in the specific surface area with an increase in n ads , i.e. with changes in adsorption state at multilayer adsorption, can be discussed (Adolphs and Setzer, 1998). A water molecular area of 0.114 nm 2 was adopted for the specific surface area calculation (Brunauer and Greenberg, 1962).…”

Section: (A)mentioning

confidence: 99%

Nano-structural Changes of C-S-H in Hardened Cement Paste during Drying at 50°C

Aono

Matsushita

Shibata

et al. 2007

ACT

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Pore structural changes in hardened cement pastes, subjected to drying and wetting/drying cycles, were studied at micrometer and nanometer levels. Characterization techniques included Nuclear Magnetic Resonance (NMR), nitrogen and water vapor adsorption, mercury intrusion porosimetry (MIP) and under-water weighing. Coarsening of pore structure was observed with MIP and increase in the true density of C-S-H was suggested by the result of under-water weighing. Decrease in specific surface area due to drying was observed with nitrogen adsorption, and water vapor adsorption associated with Excess Surface Work (ESW) analysis suggested a development of cohesive structure in C-S-H. NMR confirmed polymerization of silicate anion chains. The drying-induced coarsening of pore structure is probably attributed to polymerization of silicate anion chains and development of cohesive structure in C-S-H.

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“…An adsorbed complete wetting film remains stable as long as dΠ(h)/dh < 0 (16) which is equivalent to the Landau-Lifshitz [27] condition…”

Section: Final Adsorption Equationsmentioning

confidence: 99%

“…A comparison is given for over 300 isotherms in [15]. The depth of the minimum Φ min gives as a rule the loss of degree of freedom of an adsorbed molecule, and therefore it is suitable to characterize the sorption energies [16]. A solution at the minimum…”

Section: Theorymentioning

confidence: 99%

Thermodynamics and Modeling of Sorption Isotherms

Adolphs

2016

Chemie Ingenieur Technik

Self Cite

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An extended version of the thermodynamic computation model for sorption isotherms and capillary condensation is introduced. With the combination of the excess surface work (ESW) and disjoining pressure approach sorption isotherms for various pore size distributions of cylindrical and slit-like mesopores are successfully modeled. The main idea is that during adsorption on pore walls the approaching films will collapse and capillary condensation proceeds, while evaporation is described with a modified Kelvin equation. In both cases adsorption and desorption, the surface tension dependency on the pore size is considered.

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Description of Gas Adsorption Isotherms on Porous and Dispersed Systems with the Excess Surface Work Model

Cited by 38 publications

References 12 publications

A numeric model for the kinetics of water vapor sorption on cellulosic reinforcement fibers

A numeric model for the kinetics of water vapor sorption on cellulosic reinforcement fibers

Nano-structural Changes of C-S-H in Hardened Cement Paste during Drying at 50°C

Thermodynamics and Modeling of Sorption Isotherms

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