Gd(III) Adsorption on the DTPA-functionalized chitosan/magnetite nanocomposites

The method for chitosan (CS) covalent immobilization onto NH2-functionalized magnetite nanoparticles surface is presented. Covalent binding of CS to the magnetite surface proceeds using a free -CH2OH group of CS and a NH2-group of magnetite with epichlorohydrin (ECH) as a cross-linker. The obtained nanocomposites were functionalized by diethylenetriaminepentaacetic acid (DTPA)-groups. Composites were characterized by elemental analysis, FTIR, XPS and ASAP methods. The total content of organic phase (CS-DTPA) in the hybrid material, appreciated by thermogravimetric analysis (TGA), was 3.7%. Considering the atomic ratio between oxygen in CS and oxygen in ECH residue, the chemical structure of the hybrid material is proposed. The adsorption of Gd-DTPA and Gd3+ on the obtained nanocomposite was studied. The Freundlich isotherm fits all the experimental data better than the Langmuir adsorption.