Removal of heavy metal ions by magnetic chitosan nanoparticles prepared continuously via high-gravity reactive precipitation method.

This study aimed to provide a continuous method for the preparation of magnetic FeO/Chitosan nanoparticles (FeO/CS NPs) that can be applied to efficient removal of heavy metal ions from aqueous solution. Using a novel impinging stream-rotating packed bed, the continuous preparation of FeO/CS NPs reached a theoretical production rate of 3.43kg/h. The as-prepared FeO/CS NPs were quasi-spherical with average diameter of about 18nm and saturation magnetization of 33.5emu/g. Owing to the strong metal chelating ability of chitosan, the FeO/CS NPs exhibited better adsorption capacity and faster adsorption rates for Pb(II) and Cd(II) than those of pure FeO. The maximum adsorption capacities of FeO/CS NPs for Pb(II) and Cd(II) were 79.24 and 36.42mgg, respectively. In addition, the FeO/CS NPs shown excellent reusability after five adsorption-desorption cycles. All the above results provided a potential method for continuously preparing recyclable adsorbent with a wide prospect of application in wastewater treatment.