Preparation, characterization and application of superparamagnetic iron oxide nanoparticles modified with natural polymers for removal of 60Co-radionuclides from aqueous solution

Superparamagnetic iron oxide nanoparticles (IOMNPs) coated with natural polymers, starch (IO-S MNPs) and dextrin (IO-D MNPs), were synthesized by modified co-precipitation method. IO and hybrid-IO-MNPs were characterized by XRD, SEM, HRTEM, FT-IR spectroscopy, vibrating sample magnetometer (VSM) and zeta potential (ZP). IO-S MNPs and IO-D MNPs have IO core-shell structure with core of 10.8 nm and 13.8 nm and shell of 7.5 nm and 5.9 nm, respectively. The efficiency of the hybrid IO-MNPs for sorption of Co-60(II)-radionuclides from aqueous solution was investigated under varying experimental conditions. Kinetic data were described well by pseudo-second-order mode, sorption isotherms were fitted quite with Freundlich model with maximum adsorption capacity 36.89 (mmol center dot g(-1))/(L center dot mmol(-1)) n for IO-S MNPs and 24.9 (mmol center dot g(-1))/(L center dot mmol(-1))(n) for IO-D MNPs. Sorption of Co-60-radionuclides by IO-S MNPs was suppressed with salinity and most of the adsorbed Co-60 onto IO-S MNPs could be remove with 0.1 M HCl solution. IO-S MNPs exhibits superparamagnetic properties, easier separation according to higher saturation magnetization (47 emu/g) and better adsorption for Co-60-radionuclides than IO-D MNPs.