Powder Surface Area and Porosity

Lowell, S.; Shields, Joan E.

doi:10.1007/978-94-009-5562-2

Cited by 403 publications

(386 citation statements)

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“…The adsorbent capacity and the intensity of adsorption can be measured from the values of the intercept (lna) and the slope (1/b) in the Freundlich isotherm (Lowell and Shields 1991). In the present study, it was found that the sorption capacity of the adsorbent decreased with an increase in temperature (Table 3), which accounts for the reduced monolayer moisture values at higher temperatures.…”

Section: Resultssupporting

confidence: 50%

Moisture sorption characteristics of wadi, a legume-based traditional condiment

et al. 2011

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Moisture sorption characteristics of wadi, a condiment in the Indian Subcontinent, were investigated at temperature of 15-45°C and water activities (a w ) of 0.11-0.97. The sorption isotherms were sigmoidal. Nine different mathematical models were found to effectively describe the moisture sorption data on the basis of regression analyses and goodness of fit. Each model was statistically evaluated by means of percent root mean square and coefficient of determination. The GAB model gave the best fit in the entire range of a w . Temperature dependence of the GAB constants and good fit were determined. Using the Caurie's model, the properties of sorbed water, such as monolayer moisture content, number of adsorbed monolayers, density of sorbed water, bound water content and surface area of adsorption, which decreased with an increase in temperature, were calculated. The monolayer moisture content ranged from 102.7 to 128.7 g/kg solids in wadi. The optimum storage temperature and a w for wadi were 15-25°C and <0.7, respectively.

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Section: Resultssupporting

confidence: 50%

Moisture sorption characteristics of wadi, a legume-based traditional condiment

et al. 2011

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“…The nitrogen adsorption isotherm of an aluminum-coated quartz crystal microbalance shows that the aluminum surface has no significant porosity. 41 An analysis of the nitrogen isotherm of three different samples based on the BET-method gave a surface roughness of 1.12 cm2/cm2.…”

Section: Discussionmentioning

confidence: 99%

Monomolecular layers and thin films of silane coupling agents by vapor-phase adsorption on oxidized aluminum

Kurth¹,

Bein²

1992

J. Phys. Chem.

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Thin films of tetraethoxysilane [TEOS], (3-bromopropyl)trimethoxysilane [BPS], trimethoxyvinylsilane [VS], and 3-(trimethoxysily1)propyl methacrylate [TPM] on oxidized aluminum surfaces have been investigated by reflection-absorption FTIR spectroscopy, ellipsometry, contact angle, and quartz crystal microbalance (QCM) measurements. Gravimetric measurements with the QCM can reveal quantitative aspects of adsorption and film formation, even for films as thin as monolayers. Adsorption of these silane coupling agents from solution typically produces multilayer films. Vapor-phase adsorption of TEOS and TPM at room temperature results in monomolecular layers. The coupling agents VS and BPS require additional heating after the vapor-phase adsorption to initiate the hydrolysis and condensation reactions necessary for the surface attachment, which produces one to three layers. For vapor adsorbed films a packing density of 4-7 molecules/nm2 was found. The data strongly suggest that the organic moieties in several of these films have a preferential orientation on the surface; they can be viewed as two-dimensional, oligomeric siloxane networks with oriented organic chains. Subsequent heating of TPM films results in structural rearrangements; heating of TEOS results in complete condensation to Si02 films.

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“…The Ar sorption isotherms collected at liquid nitrogen temperature (-196 o C) were analyzed using Brunauer, Emmet, Teller (BET) equation and non-local density functional theory (NLDFT) [33][34][35][36][37][38] to reveal the SSA and pore-size distributions (PSD) of CDC. Quantachrome's data reduction software Autosorb v.1.27 [ 3 1 ] was employed for these calculations.…”

Section: Methodsmentioning

confidence: 99%

Carbide-Derived Carbons: Effect of Pore Size on Hydrogen Uptake and Heat of Adsorption

Yushin

Dash

Jagiełło³

et al. 2006

Adv. Funct. Mater.

380

259

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Cryoadsorption is a promising method of enhancing gravimetric and volumetric onboard H 2 storage capacity for future transportation needs. Inexpensive carbide-derived carbons (CDCs), produced by chlorination of metal carbides, have up to 80 % open-pore volume with tunable pore size and specific surface area (SSA). Tuning the carbon structure and pore size with high sensitivity by using different starting carbides and chlorination temperatures allows rational design of carbon materials with enhanced C-H 2 interaction and thus increased H 2 storage capacity. A systematic experimental investigation of a large number of CDCs with controlled pore size distributions and SSAs shows how smaller pores increase both the heat of adsorption and the total volume of adsorbed H 2 . It has been demonstrated that increasing the average heat of H 2 adsorption above 6.6 kJ mol -1 substantially enhances H 2 uptake at 1 atm (1 atm = 101 325 Pa) and -196 °C. The heats of adsorption up to 11 kJ mol -1 exceed values reported for metal-organic framework compounds and carbon nanotubes. Cryo-adsorption is a promising method of enhancing gravimetric and volumetric onboard H 2 storage capacity for the future transportation needs. Inexpensive carbide-derived carbons (CDC), produced by chlorination of metal carbides, have up to 80% open pore volume with tunable pore size and specific surface area (SSA). Tuning the carbon structure and pore size with high sensitivity by using different starting carbides and chlorination temperatures allows rational design of carbon materials with enhanced C-H 2 interaction and thus increased hydrogen storage capacity. Systematic experimental investigation of a large number of CDC with controlled pore size distributions and SSA show how smaller pores increase both the heat of adsorption and the total volume of adsorbed H 2 . It has been demonstrated that increasing the average heat of H 2 adsorption above 6.6 kJ/mol substantially enhances H 2 uptake at 1 atm and -196 o C. The heats of adsorption up to 11 kJ/mol exceed values reported for metal-oxide framework compounds and carbon nanotubes.

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Powder Surface Area and Porosity

Cited by 403 publications

References 0 publications

Moisture sorption characteristics of wadi, a legume-based traditional condiment

Moisture sorption characteristics of wadi, a legume-based traditional condiment

Monomolecular layers and thin films of silane coupling agents by vapor-phase adsorption on oxidized aluminum

Carbide-Derived Carbons: Effect of Pore Size on Hydrogen Uptake and Heat of Adsorption

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