Preparation of crosslinked chitosan magnetic membrane for cations sorption from aqueous solution.

The chitosan magnetic membrane was prepared in order to insert magnetic properties to the membrane that could be used for the removal of cations from the aqueous solution. The crosslinked magnetic membrane was compared with pristine chitosan membrane in term of stability, morphology and cations adsorption capacity. The fabricated magnetic materials are thermally stable as shown by Thermogravimetric curves. Membrane contain nickel magnetic particles CHNiF-G shows high thermal stability compared to the other membranes. The FTIR spectroscopy showed successful preparation of chitosan magnetic membrane. SEM micrographs showed the rough surface of membrane with increased porosity. The prepared chitosan membranes were applied to cations such as copper, nickel and lead in dilute aqueous solution. Chitosan membrane showed the following adsorption order for metallic cations Cu 2+ > Ni 2+ > Pb 2+ , while the chitosan membrane containing nickel magnetic nanoparticles CHNiF-G showed higher capacity, 3.51 mmol g −1 for copper, reflecting the improvement in adsorption capacity, since the amount of copper on pristine chitosan gave 1.40 mmol g −1 . The time required for adsorption to reach to the equilibrium was 6 h for the selected cations using different chitosan membranes. The kinetic study showed that adsorption study followed pseudo-second order kinetics. The most commonly used isotherm models Freundlich, Langmuir and Temkin isotherms were applied to experimental data using linear regression technique. However, The Temkin model fits better to experimental data.