This paper describes preparation of novel magnetic and pH-sensitive nanocomposite beads through an environmentally friendly route for protein adsorption. Magnetic Fe3O4 nanoparticles (MNPs) were modified by a binary mixture of κ-carrageenan/carboxymethyl chitosan biopolymers. The structural and adsorption properties of new product were confirmed by TEM, SEM, VSM, XRD and UV/vis techniques. The protein adsorption performance of magnetic κ-carrageenan/carboxymethyl chitosan (mCMChitoCar) was investigated using bovine serum albumin (BSA) as a model protein. The results exhibited that the adsorption kinetic followed well the pseudo-second-order kinetic model, whereas the equilibrium adsorption data were interpreted by the Langmuir isotherm model. On the basis of pH studies, the maximum adsorption of BSA onto mCMChitoCar particles was obtained in the close of isoelectric point of BSA (73.3 mg BSA/g adsorbent). The thermodynamic parameters depicted the spontaneity and exothermic nature of adsorption process.
