Greta RADEVA, Eva VALCHEVA, Stefka VELEVA

The Role of the Entropy Factor on the Adsorption of an Optical Brightener on Pulp

The present paper reports results of the thermodynamic study of adsorption of 2 optical brighteners (Tinopal UP and Leucophor AP) on pulp. The entropy non-homogeneity of the pulp surface was confirmed and the coefficients of entropy non-homogeneity were determined. The entropy effect on the variation of Gibbs free energy of the process studied was followed.

Anahtar Kelimeler:

Optical brighteners, pulp, adsorption, entropy non-homogeneity

The Role of the Entropy Factor on the Adsorption of an Optical Brightener on Pulp

Keywords:

Optical brighteners, pulp, adsorption, entropy non-homogeneity,

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Conclusion The values of adsorption equilibrium constant are estimated at diﬀerent adsorbed amounts for 2 OBs. It is found that the overall change in adsorption heat is positive, does no depend on α , and the observed process is endothermic. The entropy values decrease with α increase because of the sites occupation and the steric hindrance that developed. The entropy non-homogeneity of the pulp surface plays the major role for determination of the Gibbs free energy. Clariant, Leucophor AP liquid, 1996, Technical and product information.
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