Development of novel naphthalimide-functionalized magnetic fluorescent nanoparticle for simultaneous determination and removal of Hg2+

Abstract Mercury (Hg) commonly found in the global environment poses a serious threat to the environment and human health because of its durability, easy transference and high biological accumulation. So, great attention has been paid to the quantification and removal of mercury. Herein, we present the synthesis and properties of a novel naphthalimide-functionalized magnetic fluorescent nanoparticle for simultaneous determination and removal of Hg2+. The proposed nanoparticle showed a good linear relation (Y = −29.12216X + 363.2597, correlation coefficient of R2 = 0.9952) between the fluorescence intensity at 540 nm and the concentration of Hg2+ varying from 0.1 μmol/L to 4.5 μmol/L. Additionally, our proposed nanoparticle exhibited excellent Hg2+-selectivity over other metal ions, which was ascribed to the formation of imide-Hg-imide complexes. The removal of Hg2+ from contaminated water samples was achieved by the aggregation-induced sedimentation (AIS) strategy. Moreover, the suspended magnetic nanoparticle could be removed by external magnetic field, and the secondary pollution was avoided.