Naphthalimide-functionalized Fe3O4@SiO2 core/shell nanoparticles for selective and sensitive adsorption and detection of Hg2+

A novel 1,8-naphthalimide-functionalized Fe3O4@SiO2 core/shell magnetic fluorescent nanoparticles (MFNPs) for simultaneous detection and adsorption of Hg2+ was designed and synthesized. A series of adsorption studies were carried out with various Hg2+ concentrations, temperature, time and pH. The maximum adsorption capacity is higher than 30 mg/g over a broad temperature (0 °C, 25 °C, and 50 °C) and pH (4–10). The results showed that MFNPs possesses an excellent reusability and the high adsorption specificity toward Hg2+. The detection limit for Hg2+ is 3.4 nM. In addition, owing to the aggregation of MFNPs occurring in the Hg2+ aqueous solution, the adsorbent was separated easily by the settlement or the external magnetic field, which facilitated the removal of Hg2+.

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► Naphthalimide-functionalized MFNPs was designed and synthesized.
► MFNPs exhibits the high selectivity and sensitivity toward Hg2+.
► MFNPs possesses good reusability and high adsorption capacity.