Dansyl derivative functionalized Fe3O4@SiO2 fluorescent probe for detection and removal of Hg2+ in aqueous solution

Abstract

In the present work, a novel dansyl group functionalized Fe₃O₄@SiO₂ magnetic nanomaterial with a core–shell structure was developed, aiming to detect and remove Hg²⁺ from aqueous media. The multifunctional nanocomposite shows excellent fluorescence sensitivity and selectivity towards Hg²⁺ over other metal ions (Na⁺, K⁺, Mg²⁺, Al³⁺, Ca²⁺, Cd²⁺, Ni²⁺, Co²⁺, Fe³⁺, Zn²⁺, Pb²⁺, Cu²⁺, Ag⁺). Concentrations as low as 10⁻⁸ M can be detected and the addition of other metal ions has a negligible influence on the fluorescence emission. Regarding the reversibility of the nanosized sensor, the fluorescence of the DAP-Fe₃O₄@SiO₂ nanocomposite in the presence of Hg²⁺ ions is found to be almost reversible when treated with iodide anion. Additionally, the nanocomposite can be easily separated from solutions by adding an external magnetic field. Moreover, the functionalized nanosphere shows a good adsorption capacity to Hg²⁺, which makes it repeatedly applicable for simultaneous Hg²⁺ sensing and removal from polluted water. These results indicate that the multifunctional nanocomposite may find potential applications for simple detection and easy removal of Hg²⁺ in biological and environmental areas.