Novel and facile synthesis of magnetic composites by a modified co-precipitation method

A simple and effective method is proposed to synthesize chitosan/magnetite (CS/MAG) and cellulose/magnetite (CEL/MAG) composites. Biopolymers were employed in bulk during the co-precipitation of magnetite, avoiding the problems associated to the polymer's solubility. FTIR and XRD analysis revealed that the polymeric template was perfectly integrated to the crystalline structure of magnetite. Measurements of zeta (Z) potential indicated that new materials present different charged surfaces depending on the biopolymer. SEM/TEM and dynamic light scattering (DLS) results demonstrated that particulated materials with average diameters lower than 1 mu m were obtained. The magnetic properties of such composites were qualitatively verified. The as-obtained hybrids composites were tested for proteins adsorption using bovine serum albumin (BSA) and insulin (Ins) as models. It was found that CS/MAG was a better protein adsorbent than CEL/MAG. One important drawback of CEL/MAG was the lack of stability under the proteins adsorption conditions. (C) 2011 Elsevier B.V. All rights reserved.