Novel biosorbent (Canola hull): Surface characterization and dye removal ability at different cationic dye concentrations

In this paper, surface of novel biosorbent (Canola hull) was characterized and its dye removal ability at different cationic dye concentrations was studied. The isoelectric point, functional groups and morphology of Canola hull were investigated as biosorbent surface characteristics. Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and UV-Vis spectrophotometry were used. Basic Blue 41, Basic Red 46 and Basic Violet 16 were used as model textile cationic dyes. The presence of functional groups onto Canola hull were investigated using FIR. The intraparticle diffusion, pseudo-first order and pseudo-second order kinetic models were examined to evaluate the kinetic data and the rate constants were calculated. The Langmuir, Freundlich and Tempkin adsorption isotherm models were applied to describe the equilibrium isotherms. Thermodynamic parameters such as free energy, enthalpy and entropy of dye adsorption were obtained. The FTIR spectrum proved the presence of functional groups such as hydroxyl and amino groups in adsorbent surface. Adsorption kinetic of dyes followed pseudo-second order kinetics. The thermodynamic studies showed that the dye adsorption onto Canola hull is spontaneous, endothermic and physical reaction. The results indicated that Canola hull could be used as a noval natural biosorbent for the removal of cationic dyes. (C) 2010 Elsevier B.V. All rights reserved.