Synergistic adsorption of Pb(II) ions by Fe3O4 nanoparticles-decorated porous BN nanofibers

Abstract

We report the synthesis of Fe3O4 nanoparticles (NPs)-decorated porous boron nitride nanofibers (BNNFs) as a novel BNNF@Fe3O4 nanocomposite via a solvothermal method. One-dimensional porous BNNFs with high porosity are utilized as carrier for supporting and immobilization of Fe3O4 NPs with average diameters of ∼7 nm. Magnetic measurement confirms that nanocomposites are in superparamagnetic state. The nanocomposites with even sparsely loaded Fe3O4 NPs can be easily operated in a low magnetic field. Furthermore, the BNNF@Fe3O4 nanocomposites with sparsely loaded Fe3O4 NPs exhibit remarkable adsorption effect on Pb(II) ions in accordance with the Langmuir and the pseudo-second-order kinetic models. The synergistic adsorption of Pb(II) on BNNF@Fe3O4 nanocomposites are further studied via the adsorption of Pb(II) using BN nanocomposites with different loading amount of Fe3O4 NPs. The results indicate that the strong electrostatic interaction between BNNFs and Pb(II) results in the initial fast adsorption of Pb(II) on the surface of BNNFs, and the weak electrostatic force of Fe3O4 leads to the subsequent adsorption of Pb(II) on Fe3O4, showing an interesting component-ratio related synergistic effect. The synergistic adsorption mechanism clarified in this study will advance the fundamental knowledge and scientific understanding of the nanocomposite adsorbents.