Highly efficient removal of heavy metal ions by carboxymethyl cellulose-immobilized Fe3O4 nanoparticles prepared via high-gravity technology.

The aim of this study is to explore facile and large-scale method for the preparation of magnetic adsorbent materials with high-efficient heavy metal removal performance. Here, based on the process intensification of high-gravity technology, the carboxymethyl cellulose-immobilized Fe3O4 nanoparticles (CMC-Fe3O4) were continuously synthesized via impinging stream-rotating packed bed. With a theoretical production rate of 2.35 kg h-1, the as-prepared CMC-Fe3O4 exhibited better adsorption capacity and faster rate for Pb(II) than those of pure Fe3O4, and the maximum adsorption capacity of Pb(II) reached up to 152.0 mg g-1. It was found that the adsorption data of Pb(II) onto CMC-Fe3O4 fit well to pseudo-second order kinetic model and Langmuir isotherm model. Moreover, the as-prepared adsorbent exhibited good reusability after five adsorption-desorption cycles. Overall, the high-gravity technology can be employed for the preparation of high-performance nano-adsorbent and has a great potential in the application of heavy metal removal.