Insight into the adsorption mechanisms of vanadium(V) on a high-efficiency biosorbent (Ti-doped chitosan bead)

In this present study, a new chitosan bead modified with titanium ions (TiCB) was prepared and employed for the adsorption of vanadium ions from aqueous solutions. Batch adsorption experiments were performed to research the effect of various factors, including pH, temperature, contact time and initial concentration of vanadium(V) ions. The adsorption of vanadium was followed by the pseudo second-order kinetic and the Langmuir isotherm model, with a remarkable maximum adsorption capacity of 210 mg/g. The analysis of thermodynamic parameters (Delta G degrees, Delta H degrees and Delta S degrees) revealed that the nature of adsorption was feasible, spontaneous (Delta G degrees <0) and endothermic (Delta H degrees >0) process. FTIR, EDS, EMI and XPS studies suggested that the mechanisms of adsorption were possibly attributed to electrostatic attraction, ligand-exchange and redox reaction between TiCB and vanadium ions. (C) 2015 Elsevier B.V. All rights reserved.