Influence of Surface Wettability on Adsorption Isotherms of Water Vapor

Churaev, N. V.; Setzer, Μ.J.; Adolphs, Jürgen

doi:10.1006/jcis.1997.5292

Cited by 33 publications

(27 citation statements)

References 13 publications

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“…However, the same behaviour is shown in the paper by Chen and Wangaard (1968) for a different species, but in this case, the desorption cycle from the wet state is for a sample of originally dry wood that was subsequently equilibrated over water. Churaev et al (1998) discussed the nature of water vapour sorption isotherms on porous surfaces where there is incomplete wetting of the substrate during the sorption process. This involves calculations of contact angles formed between the convex capillary menisci in narrow pores at RH values below saturation.…”

Section: Resultsmentioning

confidence: 99%

The reduction in the fibre saturation point of wood due to chemical modification using anhydride reagents: A reappraisal

Hill

2008

HFSG

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The data from a previous study of the moisture adsorption of Corsican pine modified with linear chain carboxylic acid anhydrides (acetic, propionic, butyric, valeric, hexanoic) has been reanalysed so that moisture content is reported as a percentage of cell wall mass only. As part of this work, the change in fibre saturation point (FSP, determined from fits of the Hailwood-Horrobin model) of the modified wood has been determined as a function of weight percentage gain (WPG). The change in FSP is not determined by the extent of hydroxyl substitution of the cell wall, but is related to WPG only (as reported previously). This is also true for the relationship between monolayer water, polylayer water, molecular weight per sorption site at saturation and WPG. However, there is no simple linear relationship between calculated FSP and WPG. When the FSP was determined by solute exclusion methods, the reduction thereof could be simply explained as due to bulking of the cell wall by the bonded acyl substituents. This is not the case when the FSP is determined from adsorption isotherms. This result is interpreted as an ambiguity of determination of FSP from projections of sorption isotherms. Differences in FSP determined by the two methods (sorption versus solute exclusion) are considered to be due to incomplete wetting of the lignocellulosic material when absorbing moisture from the initial dry state.

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Section: Resultsmentioning

confidence: 99%

The reduction in the fibre saturation point of wood due to chemical modification using anhydride reagents: A reappraisal

Hill

2008

HFSG

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“…The concept of surface wettability of water surfaces in microcapillaries has been used more recently in a theoretical treatment of sorption isotherms. 35 It should be noted in this context that two types of hysteresis can be observed with cellulose, or a lignocellulosic material ( Fig. 1).…”

Section: Introductionmentioning

confidence: 98%

The water vapor sorption behavior of natural fibers

Hill

Norton

Newman

2009

J of Applied Polymer Sci

360

296

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The water vapor sorption behavior of a range of natural fibers (jute, flax, coir, cotton, hemp, Sitka spruce) has been studied. The data were analyzed using the Hailwood Horrobin model for isotherm fitting and determination of monolayer moisture content. The Hailwood Horrobin model was found to provide good fits to the experimental data. The extent of hysteresis exhibited between the adsorption and desorption isotherms was dependent on fiber type studied and was larger with high lignin compared with low lignin content fibers. The area bounded by the hysteresis loop decreased as the isotherms were performed at progressively higher temperatures. This behavior is consistent with sorption interactions occurring with a glassy solid below the glass transition

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“…The term Πh is equivalent to the expression ΓΔm, which was introduced in [11] as a new thermodynamic function called excess surface work Φ. It is defined [12]: Excess surface work ESW = surface free energy + isothermal isobaric work of sorption.…”

Section: Theorymentioning

confidence: 99%

“…Further, for adsorption the sum of two exponential functions for the film thickness was applied, and the surface tension dependence on the pore size was considered. However, together with Churaev the author showed already in [10], that a sum of two exponential functions is helpful for the description of wetting phenomena in very large pores with pores sizes of several microns, but not necessarily for micropores as in MCM-41 zeolites. Further in the results ( [9] Tab.…”

Section: Introductionmentioning

confidence: 96%

Thermodynamics and Modeling of Sorption Isotherms

Adolphs

2016

Chemie Ingenieur Technik

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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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Influence of Surface Wettability on Adsorption Isotherms of Water Vapor

Cited by 33 publications

References 13 publications

The reduction in the fibre saturation point of wood due to chemical modification using anhydride reagents: A reappraisal

The reduction in the fibre saturation point of wood due to chemical modification using anhydride reagents: A reappraisal

The water vapor sorption behavior of natural fibers

Thermodynamics and Modeling of Sorption Isotherms

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