Non linear modelisation of dyes removal from aqueous solution by using sorption onto Luffa cylindrica fibers

Abstract

The biosorption of indigo carmine (IC) and methylene blue (MB) using a lingo-cellulosic fiber: Luffa cylindrical was carried out in this study. It was shown in this work, that biosorption capacity of dyes increase with increase of initial dyes concentrations and mass of biomass and to decrease with the raise of salt and temperature. Optimal parameters of the biosorption of dyes onto Luffa cylindrica were obtained after 150 min and pH 10 for MB and 525 min and pH 2 for IC. The experimental equilibrium data were studied employing the isotherms of Langmuir, Freundlich, Jovanovic, Temkin, Redlich–Peterson, Toth, Sips, and Brouers–Sotolongo. The experimental data fitted very well with the Bouers-Sotolongo isotherm for MB and the Toth isotherm for IC. Concerning IC, the value of maximum biosorption capacity (Q_m = 6.876 mg/g) was close to the experimental value (Q_m = 6.874 mg/g), and the correlation coefficient (R²) was 0.996. While for MB, the value of maximum biosorption capacity (Q_m = 13.849 mg/g) was close to the experimental value (Q_m = 13.900 mg/g), and the correlation coefficient (R²) was 0.992. In order to study the biosorption kinetics, four kinetics models such as pseudo-first order, pseudo-second order, Elovich and Brouers-Sotolongo were studied. The Brouers-Sotolongo (2,α) fractal  model appears to be the best model to fit the experimental data.