Kinetic and thermodynamicstudy of the adsorption of twodyes:brilliant green and eriochrome black T using a natural adsorbent "sugarcane bagasse".

Abstract

The aim of this study is to find an effective and inexpensive natural material used as an adsorbent for the textile dyes removal. Indeed, we have been interested in testing the effectiveness of sugarcane bagasse (SB) as a biosorbent to remove brilliant green (BG) and eriochrome black T (EBT). In our experiments, different parameters such as initial dye concentration, contact time, adsorbent dose and solution temperature have been analyzed in a batch system. Similarly, the studies of thermodynamic, kinetic and adsorption isotherm have been evaluated. The sugarcane bagasse (SB) without any modification has been characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The maximum adsorption capacity of BG and EBT on the SB adsorbent has been 37.58 and 12.30 mg.g -1 respectively, for a concentration of 40mg.g -1 at a temperature of 20°C and 1g.L -1 of adsorbent. The results of the adsorption kinetics have proved that the pseudo-second order model correctly describes the adsorption phenomenon of the two dyes studied. The Langmuir and Freundlich isotherms have been applied to experimental equilibrium data. The various thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°) and standard entropy (ΔS°) have indicated that the adsorption is spontaneous and endothermic in brilliant green and exothermic in eriochrome black T.