Adsorbent Granules Research Articles

Dilatometric measurements on zeolites

1. A method for measuring the relative elongations of both granulated adsorbents and adsorbents in the form of small single crystals was proposed. 2. The dilatometric characteristics of the granules cannot be a precise picture of the dilatometry characteristic of the crystals of which the granules consist.

Microporous carbon adsorbent systems Communication 3. Experimental estimation of micropore system parameters

1. A method has been developed for the experimental determination of the characteristic dimensions of the mesopore and micropore zones of active carbons based on precipitation of carbon within the adsorbent granules and subsequent grinding and measurement of its adsorption properties and the external surface after grinding. 2. In the AC-30 active carbon studied, the size of the unit micropore zones was 220 nm and that of the unit mesopore zones was 540 nm.

Measurement of rat serum corticosterone using radiostereoassay kit for cortisol (author's transl)

A very simple technique for measurement of rat serum corticosterone with radiostereoassy kit using 75Se-cortisol was devised. Only 25--50 microliter serum was required for this assay. The serum sample was first diluted to 300 microliter with water and heated in a glass tube to denature the endogeneous cortisol binding protein. Then an aliquot of the sample was transferred into an assay vial containing 75Se-cortisol, cortisol binding protein and adsorbent granules. After rotated, an aliquot of the supernatant was taken for counting. High level of rat serum corticosterone was measured with satisfying accuracy by dilution with water. Serum corticosterone levels in 7 normal female Sprague-Dawley rats (7 weeks old, Ca 200g body weight) at 2.00 pm were 29.5 +/- 12.2 microgram/dl (mean +/- SD). The levels were lower and higher in rats treated with dexamethasone and with 1-18 ACTH, respectively.

Calculation of internal diffusion coefficients and diffusion resistance of energy into microporous formations for adsorbent granules with a biporous structure

Methods were discussed for calculating the internal diffusion coefficients and the diffusion resistance of entry into microporous formations for adsorbent granules with a biporous structure from the experimental kinetic curves in the case of linear adsorption isotherms. For this it is necessary to determine: a) the first three moments of the kinetic curve for one granule of the adsorbent; or b) the first two moments for two granules of one sorbent with a different size.

Dynamics of adsorption in a stationary bed of adsorbent granules with a bidisperse porous structure in the case of linear adsorption isotherms

Equations were obtained that make it possible to determine the mass transfer coefficients in a bed of adsorbent granules with a bidisperse porous structure from the integral characteristics of the dynamic exit curves for various conditions when entering the bed.

Effect of grain diameter and uniformity of adsorbent granules on the efficiency of gas chromatographic columns of various diameters

The effect of sorbent grain diameter and granule uniformity on the efficiency and resolving power of columns of various diameters has been studied. It is shown that for columns of small diameter the grain size has a significant effect on efficiency and resolving power, while for columns of large diameter non-uniformity of the sorbent granules is of greater importance.

Predictive equations in gas adsorption kinetics

The experimental method of determining the operative parameters of adsorptive capacity and rate in the gas adsorption kinetics of packed bed sorbents relies upon the linear relationship between gas breakthrough time and sorbent weight. The slope and intercept of the straight line, resulting from such a plot, yields values for the gas saturation capacity and adsorption rate constant of the adsorbent. This relationship is shown in the modified Wheeler adsorption equation, originally derived from a continuity equation of mass balance between the gas entering an adsorbent bed and the sum of the gas adsorbed by plus that penetrating through the bed. We have found that for wellpacked adsorbent beds, the Dubinin-Polanyi equations for predicting adsorption space at equilibrium, based upon prior characterization of an adsorbent with a reference gas, could also be applied to gas flow conditions, and the kinetic capacity of the adsorbent predicted within close limits. Although no theoretical relationship exists for prediction of the adsorption rate constant, recent gas tests at high linear flow velocities have shown experimental evidence of the mass transfer limiting value for the rate constant. The functionalities of the kinetic saturation capacity and the mass transfer limited value for the adsorption rate constant have been incorporated into the modified Wheeler adsorption equation to provide an expanded equation permitting prediction by calculation of the breakthrough time of a gas through a well-packed bed of adsorbent granules.

Beeinflussung der remissionsmessung an dünnschichtchromatogrammen durch arbeitstechnische faktoren : II. Mitt. wahl der methode, beschaffenheit der stationären phase und applikation der substanzen

Influence of chromatographic factors on remission measurements on thin-layer chromatograms. Part I. Choice of the method, properties of the stationary phase and application of substances Some introductory remarks are made concerning the choice of the determination method, and different methods are compared. Chromatographic factors affecting the spectrophotometric evaluation of thin-layer chromatograms are discussed. In connection with this, the layer thickness of the stationary phase, the grain-size distribution and the pore diameter of the adsorbent were investigated. In trace analyses using a stationary phase consisting of thin layers of finely granulated adsorbents having a small pore diameter, sensitivity can be increased by a factor of 10. It was found that there was no relationship between the direction in which the layer had been applied on the plates and that in which chromatography or measurement was carried out. The manner of applying the solutions to be examined is also discussed, and the advantages of applying the solution as streaks or round spots, respectively, are pointed out. For this purpose the polarity of the standard and test solutions should be considered so that no disturbances due to formation of zones differing in area will occur. To obtain calibration curves according to the Kubelka—Munk equation, the ratio of the measured area to the zone area should be kept constant.

XIII.—The Adsorption of Gas under Pressure

Summary1. Experiments made at 15° C. with various adsorbents and gases (chiefly nitrogen and hydrogen) show that a cylinder filled with adsorbent granules has a capacity for dry gas under a given pressure which is generally greater than its capacity when containing no adsorbent. For example, a cylinder charged with nitrogen at 35 atmospheres has its capacity increased by 66 per cent. by filling it with cocoanut charcoal.2. Sudden outbursts of firedamp in coal-mines are the result of releasing immense quantities of gas adsorbed under pressure in coal.3. The logarithmic relation derived by Williams is shown to apply to the adsorption isotherms of gases above their critical temperature up to pressures of 100 atmospheres, providing a correction be applied for the gas in the capillaries which is not adsorbed, but which exists under simple compression.