Abstract

Research on adsolubilization to fibrous proteins, such as collagen, has received little attention despite its academic relevance and potential industrial applications.

The aim of this work was to study the influence of different parameters on adsolubilization onto collagen fibres using 2-naphthol as a model substance in order to verify the feasibility of this process in removing organic contaminants from wastewaters. The collagen fibres were previously or simultaneously treated with an anionic surfactant under mild acidic aqueous conditions to form the admicelles.

The following parameters were considered: shaking time, surfactant type (sodium dodecyl sulphate and sodium dodecylbenzene sulphonate); influence of pH; presence of electrolytes and polarity of the medium. Adsolubilization isotherms were obtained at 10, 20, 25, 30 and 35°C and the kinetic study of adsolubilization was also measured. Thermodynamic parameters such as enthalpy change, entropy change and free energy change were calculated by applying the van’t Hoff equation for adsolubilization of 2-naphthol.

The higher adsolubilization capacity of 2-naphthol was reached at acidic pH and equilibrium was achieved after two hours of treatment. The presence of ethanol in the batch considerably lowered the adsolubilization capacity of fibrous collagen. Thermodynamic parameters indicated that the adsolubilization process is exothermic and spontaneous. The kinetic study revealed that adsolubilization of 2-naphthol onto collagen fibres is best described by a pseudo-second order model.

Our results open the door to the use of collagen fibres in the separation of organic contaminants from wastewaters through adsolubilization.