EQUILIBRIUM AND KINETIC MODELING OF ADSORPTION OF DISPERSE BLUE 79 ONTO DIFFERENT ADSORBENTS

Abstract

Azo dyes are generally used in food, cosmetic, textile, pharmaceutical, and leather industries. Many of these dyes are carcinogens and need a treatment. The aim of the present study was to use chitosan (CHT), phosphogypsum (PG) and natural phosphate (NP) powders for the removal of Disperse Blue 79 (DB 79) from aqueous solution. The effects of contact time, initial dye concentration, absorbents doses, solution pH, and temperature on the batch adsorption process were systematically studied. Isotherm models were applied to the experimental equilibrium data and pseudo-first order, pseudo-second order kinetic models were used to describe the kinetic data and to evaluate the rate constants. The thermodynamic parameters, such as the changes in enthalpy, entropy, and Gibbs free energy were also studied. The results show that the chitosan, phosphogypsum and natural phosphate could be used for the removal of DB 79 in wastewater treatment.