Highly efficient removal of heavy metal ions by amine-functionalized mesoporous Fe3O4 nanoparticles

Amine-functionalized mesoporous Fe3O4 nanoparticles (AF-Fe3O4) were developed for the highly efficient removal of toxic heavy metal ions from water. AF-Fe3O4 were prepared by a new cost-effective and environmentally friendly procedure. The maximum amino-group grafted onto AF-Fe3O4 is 0.1790 μg/mg by ninhydrin test. AF-Fe3O4 can be simply recovered from water with magnetic separations at low magnetic field within 1 min. Each adsorption of 50 mL 5 mg/L of Pb(II), Cd(II), and Cu(II) onto 10 mg of AF-Fe3O4 reached equilibrium within 120 min at pH 7.0. It agreed well to the Langmuir adsorption model with maximum adsorption capacities for Pb(II), Cd(II), and Cu(II) from 369.0 to 523.6 mg/g, which is larger than some other reports. The adsorption rates of Pb(II), Cd(II), and Cu(II) on AF-Fe3O4 fit pseudo-second order kinetic models (R2 > 0.99). Thermodynamic studies illustrated the adsorption process was endothermic and spontaneous. AF-Fe3O4 was able to remove over 98% of Cu(II), Cd(II) and Pb(II) in 50 mL of solution containing 5 mg/L metal ions at optimized conditions.

Graphical abstractAmine-functionalized mesoporous Fe3O4 nanoparticles (AF-Fe3O4) were developed for the highly efficient removal of heavy metal ions from water with high adsorpting capacity under optimum conditions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Amine-functionalized mesoporous Fe3O4 nanoparticles were used to adsorb metal ions. ► Heavy metal ion adsorption capabilities of AF-Fe3O4 are high for AF-Fe3O4. ► The adsorptions are spontaneous and endothermic. ► The adsorption could be well interpreted by the Langmuir model. ► The adsorption of Pb(II), Cd(II), and Cu(II) fit pseudo-second order kinetic models.