29—the Diffusion of Direct Dyes in Cellulose

Standing, H. A.; Warwicker, J. O.; Willis, Hector F.

doi:10.1080/19447024708659390

Cited by 44 publications

(9 citation statements)

References 11 publications

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“…Representing this behaviour by the equation D = a C f + Do, (2) where cjis the concentration of absorbed dye, expressed in mole/kg of dry cellulose, the constants a and DO are found to have the following values: Chrysophenine G, a= 0.55 X 10-6 kg c m 2 sec-1 mole-1, DO = 0.021 x 10-6 cmz/sec ; dye A, a = 0.07 X kg cm2 sec-1 mole-1, DO = 0,017 x 10-6 cm2/sec. Small quantities of pyridine in the dyebath reduce the affinity of Chrysophenine G for cellulose and correspondingly increase the diffusion coefficient tenfold (fig.…”

Section: Integral Diffusion Coefficients Have Been Calculated From Th...mentioning

confidence: 99%

The diffusion of dyes in cellulose

Heritage¹

1958

Trans. Faraday Soc.

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Measurements have been made of the rate of diffusion of a series of dyes through Cellophane membranes over a wide range of concentrations, particular attention being paid to the effect of the affinity of the dye for the cellulose. It has been shown that, (i) the integral diffusion coefficient for dyes with a low affinity for cellulose is independent of concentration except in the most dilute solutions, decreasing then with increasing dilution, (ii) the permeability of the membrane towards a dye of low affinity is reduced when the carboxyl content of the cellulose is increased, (iii) with increasing affinity of the dye, the diffusion coefficient decreases correspondingly, (iv) dyes of higher affinity show a linear increase of diffusion coefficient with concentration, and (v) an acid dye with a pronouncedy amphipathic constitution is strongly absorbed by the cellulose and differs from the other dyes in that the diffusion coefficient falls as the concentration rises.

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Section: Integral Diffusion Coefficients Have Been Calculated From Th...mentioning

confidence: 99%

The diffusion of dyes in cellulose

Heritage¹

1958

Trans. Faraday Soc.

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“…Also, the experiments carried out at 20°C (Co ranging between 0.066 and 0.191) lead to n values which lie between 0.78 and 0.99, and suggest that the glucoamylase immobilization is a firstorder process [35]. The values of n obtained at 30 or 40°C for Co higher than 0.122 support the involvement of diffusional phenomena in modifying the process kinetics [36,37].…”

Section: Discussionmentioning

confidence: 66%

Glucoamylase absorption and desorption process

Popa¹

1996

Journal of Biomaterials Science, Polymer Edition

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This paper reports the study of glucoamylase absorption and desorption processes on spherical particles constituting acrylic supports. The kinetic (reaction order, half-life of the reaction, reaction rate constant), and thermodynamic parameters (activation energy, pre-exponential factor) of the glucoamylase immobilization reaction dynamics inside the acrylic supports have been studied. Hindrance of the penetrants (protein molecules), which defeats the polymer's cohesive forces and passes through the diffusional barriers towards the sites available to receive it, denotes the influence of the diffusion phenomena, and might be expressed by the values of the effective diffusion coefficient and of the energetic parameters, as well. The desorption dynamics of glucoamylase in specific buffer concentration gradients and temperature are dependent on the eluent volume and on the protein eluate.

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“…An equation of the Freundlich type = k'c p m may be used to relate x, the overall concentration of dye adsorbed and c p , the concentration of free dye in solution in the pores and capillaries per unit volume of water, where k' and m are constants (0 < m < 1). The variable diffusion coefficient D e is given (Standing, Warwicker and Willis, 1947) by where D p , the diffusion coefficient of the free dye along the pores in the absence of absorption, is assumed constant, and v is the volume fraction of water-filled pore space. It may readily be shown from the above equations that D c is proportional to * (1 -»>>».…”

Section: Discussiononthenatureofthereaction (A) Chemical Factorsmentioning

confidence: 99%