Automatisch arbeitende Apparatur zur Oberflächenbestimmung nach BET

Schlosser, E.‐G.

doi:10.1002/cite.330311211

Cited by 22 publications

(3 citation statements)

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“…The method as given by Schlosser (1959) is a dynamic one; during an experiment the adsorbate flows continuously through the capillary tube into the adsorption vessel.…”

Section: Principle Of Operationmentioning

confidence: 99%

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Automatic and low-cost determination of BET surface areas

Bosch¹,

Peppelenbos²

1977

J. Phys. E: Sci. Instrum.

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where Pr is the relative pressure of the adsorbate, equal to absolute pressurejsaturation pressure at the temperature of the experiment, Va is the amount adsorbed (cm3 STP g-l), and C is the constant whose value depends on the heat of adsorption.Plotting the left-hand side of equation (2) as a function of P, should result in a straight line. In this case Vm can be calculated from the slope and the intercept. Vm is related to the specific surface area SBET through equation (1). Sometimes SBET is calculated from only one point of the adsorption isotherm Morrison 1952, 1953). From equation (2) it can be deduced that this method is valid only if C% 1 + l/'f'r, but a check on the assumption and applicability of the BET method is not possible.A discussion of the basic assumptions in the BET model is beyond the scope of this paper (see for instance Sing 1964). Two cases which lead to wrong results by using a one-point method should, however, be noted. In the case that an appreciable amount of micropores is present, capillary condensation will occur. The amount adsorbed will be larger than predicted by the BET equation which concerns multilayer adsorption only. Calculation of SBET from only one point of the adsorption isotherm results in a value which is too high. A plot according to equation (2) will show clearly the presence of micropores by a deviation from a straight line which is convex with respect to the abscissa. On the other hand, the adsorption might be limited by the pore diameter to only a few adsorbed layers, which results in a concave deviation indicating that equation (2) is not valid in that particular case. These possibilities might occur, notwithstanding that the condition C&l/Pr is satisfied (compare table 2).Thus for routine determinations one needs a cheap, automatic adsorption device, estimating about five points of the adsorption isotherm in a relatively short time, to check whether or not the BET equation is applicable. In this paper such a low-budget device is described. In fact it is a simplification of the apparatus developed by Schlosser (1959); its conception was already outlined by Scholten (1965). The construction and its application will be discussed. Abstract A simple adsorption apparatus for a quick and reproducible determination of Brunauer-Emmett-Teller (BET) surface areas is described. The justification of proposing this device lies particularly in its flexibility, simplicity of construction and low price (Dfl. 1200, $400 including liquid nitrogen level control). The dimensions and the influence of external variables are discussed quantitatively. An adsorption measurement proceeds as follows: the adsorbate (argon) passes through a capillary tube into the adsorption vessel, the flow being constant. The increase of pressure with time is recorded and compared with the blank (empty adsorption vessel). The blank does not depend on the adsorbent. It takes about one hour to determine a surface area of 100 m2. The reproducibility and accuracy are 3 % or better for surface areas larger than ...

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“…The method as given by Schlosser (1959) is a dynamic one; during an experiment the adsorbate flows continuously through the capillary tube into the adsorption vessel.…”

Section: Principle Of Operationmentioning

confidence: 99%

“…In this paper such a low-budget device is described. In fact it is a simplification of the apparatus developed by Schlosser (1959); its conception was already outlined by Scholten (1965). The construction and its application will be discussed.…”

mentioning

confidence: 99%

Automatic and low-cost determination of BET surface areas

Bosch¹,

Peppelenbos²

1977

J. Phys. E: Sci. Instrum.

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“…In the 1960s pressure decay was extended to measure the kinetics of gas uptake in polymers, namely, the diffusion coefficient, as well as the solubility. , The precision of pressure decay can be greatly increased if a differential pressure transducer is used to monitor the pressure difference between a reference chamber and a chamber in which sorption occurs. This differential pressure decay technique was first introduced by Schlosser in 1959 to measure the Brunauer−Emmett−Teller surface areas of powders and porous materials. Differential pressure decay was refined in later years by Haul and Dümbgen and first used to study polymers in 1976 by Koros and Paul .…”

Section: Introductionmentioning

confidence: 99%

A Static Sorption Technique for Vapor Solubility Measurements

Palamara

Davis

Suriyapraphadilok

et al. 2003

Ind. Eng. Chem. Res.

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A new experimental technique has been developed to measure the solubility of gases and vapors in polymers and other sorbents at elevated pressures. The technique involves measuring the total weight of a vessel containing the sorbent material pressurized with a vapor, assessing the amount of vapor in the headspace of the vessel with an appropriate equation of state, and evaluating the total amount of vapor in (on) the sorbent material by the difference. Adsorption isotherms for carbon dioxide and nitrogen on an activated carbon were measured with the static sorption technique. These data were found to agree well with data taken with a standard volumetric technique. Sorption data obtained using this method for carbon dioxide in poly(vinyl acetate) and propylene in poly(propylene) compare well with data acquired by established techniques. The group-contribution lattice-fluid theory equation of state was used to predict solubility in these systems, and the Panayiotou−Vera equation of state was applied to correlate the solubility data.

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