Adsorption of Co(II), Ni(II) and Cu(II) ions onto chitosan-modified poly(methacrylate) nanoparticles: Dynamics, equilibrium and thermodynamics studies

Novel chitosan/methacrylic acid nanoparticles (100-120 nm), CMA with superior adsorptive properties (195-340 mg/g) were fabricated by a polymerization reaction, characterized by FTIR, TEM, TGA and DSC methods and applied for removing Co(II), Ni(II) and Cu(II) ions from aqueous solutions using batch adsorption technique. The ionic adsorption activity and performance of CMA including isotherm, kinetics and thermodynamics were comprehensively studied to establish related fitting models. All parameters influencing the removal efficiency such as: adsorbent dose, pH, initial adsorbate concentration, contact time and temperature were considered to setup optimal adsorption conditions. The experimental data were fitted well to the pseudo-second-order kinetic model and to Langmuir model which predicted different stoichiometric temperature-independent sites (A, B and C) in CMA surface with variable capacities that bind selectively to metal ions. Thermodynamic data predicted endothermic, spontaneous and chemical adsorption process. The recoveries of the adsorbed metal ions from CMA nanoparticles were 85-90%, after three sorption-desorption cycles indicating a great promising application of CMA in metal treatments. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.