A Chemically Defined Approach to the Adsorption of Orange G on Chitosan Particles

Abstract

Textile industries produce a large quantity of effluents, which have high concentrations and variety of dyes. These substances, besides their poor aesthetic characteristics (when present in effluents), are extremely harmful to the environment. In this work, the sorption of the model dye Orange G was analyzed both in equilibrium and kinetic terms. Equilibrium experiments showed that Orange G sorption was well described by a Langmuir isotherm up to a point at which a Henry isotherm prevailed. This change in sorption mode was correlated to nonpolar interactions between dye and chitosan surface. An alternative kinetic description to the usual pseudo-order one was employed to describe the sorption of Orange G, following considerations based on ordinary collision rate theory. Both equilibrium and adsorption kinetics were heavily influenced by the presence of NaCl in the continuous phase.

Keywords:

• Chitosan
• effluent treatment
• sorption isotherms
• sorption kinetics