evaluation of effective diffusion coefficients for industrial adsorbents.
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evaluation of effective diffusion coefficients for industrial adsorbents. by P W. Hibble

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Published in Bradford .
Written in English

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M. Sc. dissertation. Typescript.

The Physical Object
Pagination1 vol
ID Numbers
Open LibraryOL13688610M

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Experimental measurement of the effective diffusion and thermodiffusion coefficients for binary gas mixture in porous media. Chemical Engineering Science , 65 (18), DOI: / Elsa du Plessis, Sonia Woudberg, J. Prieur du by: The lower diffusion coefficient in this model should be attributed to the stronger adsorption, i.e., to the reduced potentiality for a free motion of molecules. Read more Article.   Based on the molecular understanding of the interplay of diffusion and adsorption, new membrane materials can be developed and the operational conditions of gas separation membranes can be optimized. Therefore, numerous diffusion and adsorption studies are conducted to optimize membrane materials. However, in an opposite way, transport or Fickian diffusion coefficients DT Author: Juergen Caro.   The observed sorption kinetics was consistent with the finite bath diffusion, with an average value of × 10 −4 cm 2 /s for the product of the distribution coefficient and the effective diffusivity in the adsorption of Se(IV) on the iron oxide-coated granular activated carbon.

diffusion coefficient depends on concen-tration yields some average value of the diffusion coefficient over that concentration range. The integral diffusion coefficient in a concentration dependent system is defined as for the concentration range zero to CO. The approximation involved is that the D value determined from Eq. (1) is a. Diffusion coefficient is the proportionality factor D in Fick's law (see Diffusion) by which the mass of a substance dM diffusing in time dt through the surface dF normal to the diffusion direction is proportional to the concentration gradient grad c of this substance: dM = −D grad c dF dt. Hence, physically, the diffusion coefficient implies that the mass of the substance diffuses through a. Temperature and concentration dependence of diffusion coefficient in dilute solutions." A. Z. Akcasu THEORY In light scattering experiments, the diffusion coefficient is determined by representing the measured normalized intermediate scattering function S(q,t) by exp(- Dq2t). In. A corresponding‐states correlation of low‐density binary‐ and self‐diffusion coefficients is presented. The equations are simple to use, are sufficiently accurate for most calculations, and correlate those data used in their derivation somewhat better than calculations based on the Lennard‐Jones potential if potential parameters have to be estimated from the critical properties.

Fundamentals of Fluid Flow in Porous Media Chapter 3 Diffusion Coefficient: Measurement Techniques It is noteworthy that there is no well-established and universally applicable technique for measuring the molecular diffusion coefficient. Unlike the measurements of viscosity or thermal conductivity, for which standardized techniques and equipment are readily available, the measurements of mass. assuming a diffusion coefficient dependent on moisture content (Crank, [5]; Crank, [6] ; Aguerre et al., [7]). The diffusion coefficient to be determined is an effective one that involves all moisture transport mechanisms that could be involved in the drying process. The moving boundary problem is transformed in a fixed. A brief historical survey is presented on the evaluation of silica adsorbents in analytical HPLC. The theory of analytical HPLC is mostly still being based on the height equivalent to a theoretical plate concept and the van Deemter equation that was derived from gas phase adsorption involving a linear adsorption isotherm and fast mass transfer kinetics. The points of zero charge (PZC) of the adsorbents (pHPZC) were , , and to raw coconut (RC), raw coconut alkalized (RCA), and coconut shell modified with tannic acid (TCA) adsorbent.