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 Fe3O4/Chitosan nanoparticles (Fe3O4/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 Fe3O4/CS NPs reached a theoretical production rate of 3.43 kg/h. The as-prepared Fe3O4/CS NPs were quasi-spherical with average diameter of about 18 nm and saturation magnetization of 33.5 emu/g. Owing to the strong metal chelating ability of chitosan, the Fe3O4/CS NPs exhibited better adsorption capacity and faster adsorption rates for Pb(II) and Cd(II) than those of pure Fe3O4. The maximum adsorption capacities of Fe3O4/CS NPs for Pb(II) and Cd(II) were 79.24 and 36.42 mg g(-1), respectively. In addition, the Fe3O4/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. (C) 2017 Elsevier Ltd. All rights reserved.