Multifunctional Fe3O4@SiO2 nanoparticles for selective detection and removal of Hg2+ ion in aqueous solution

Abstract

In the present work, a multifunctional magnetic core–shell Fe₃O₄@SiO₂ nanoparticle decorated with a rhodamine-based receptor, which exhibits high selectivity and sensitivity toward Hg²⁺ over other metal ions in aqueous solution, has been synthesized by the graft method and characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry, and UV-vis absorption and fluorescence spectra. The multifunctional nanoparticles show superparamagnetic behavior, clear core–shell architecture, and also exhibit high optical sensing performance for the detection of Hg²⁺. The fluorogenical responses of RB-Fe₃O₄@SiO₂ are stable under a broad pH range. Additionally, these nanoparticles show high performance in the magnetic separability and effective removal of excess Hg²⁺ in water via an external magnetic field. These results indicate that these multifunctional magnetic nanoparticles may find potential and practical applications for selective detection and simple removal of Hg²⁺ in environmental, toxicological, and biological fields.