Adsorption isotherm, thermodynamic and kinetics studies of polyphenols onto tannery shavings

Shavings constitute a waste of the tannery industry. They consist of small pieces of leather cut or shaved off from the flesh side of leather to reduce the thickness or render it uniform. Vegetable extracts, which consist of polyphenolic substances, are used for tanning a variety of articles. The aim of this work was to study the adsorption capacity of tannery shavings (wet-white and chrome shavings) for vegetable extracts (polyphenols) when they are used at moderate offers and are present in aqueous solutions at the highest concentration of 2.0 g/L. Thermodynamic and kinetic parameters of the adsorption process were also determined. Both types of shavings are good adsorbents of polyphenols in aqueous solutions although wet white shavings exhibited a higher adsorption capacity. The thermodynamic study revealed that no very marked differences were observed for both adsorbents. (C) 2011 Elsevier B.V. All rights reserved.