Kinetics investigation and Equilibrium studies on the biosorption Leuco-form of Indigo Blue dye using chemically modified Coconut fibre

Abstract

In recent years, cheaply available agricultural wastes are increasingly finding useful applications in environmentally friendly ways. In this study, we investigate the effectiveness of the use of chemically modified coconut fibre in the biosorption of indigo blue dye from its solution. The influence of the variation of pH, contact time, concentration of dye and biosorbent dose on the biosorption process as well as the kinetics of the sorption process was studied. The biosorption equilibrium data were analysed with Langmuir, Freundlich and Temkin isotherms. The results showed that there was maximum percentage dye removal of 94.64 % at pH 6 within contact time of 1 hr. Similarly, 80 mg/L of biosorbent dosage and 0.05 mg/L of initial dye concentration gave the maximum percentage dye removal of 86.43 % and 95 % respectively. The Langmuir isotherm with R² value of 0.9963 was the best model to describe the equilibrium data and the biosorption process followed the pseudo second order kinetics with a rate constant k₂ value of 1.20 gmg^-1min^-1 at the initial dye concentration of 0.05 mg/L. Therefore, the chemically modified coconut fibre is shown a suitable low cost biosorbent for the treatment of indigo dye effluents.