Multifunctional Binding Strategy on Nonconjugated Polymer Nanoparticles for Ratiometric Detection and Effective Removal of Mercury Ions

Developing a multifunctional platform for the selective detection and effective removal of toxic ions is a major challenge when addressing heavy metal contamination in environmental science. Herein, novel nonconjugated polymer nanoparticles (PNPs) called mercaptosuccinic acid-thiosemicarbazide PNPs (MT-PNPs) with appealing fluorescence and stability are synthesized via facile one-step hydrothermal treatment for attractive sensing and simultaneous removal of mercury(II). Interestingly, aggregation-induced fluorescence switch-off and scattering enhancement are found upon the addition of Hg2+, rendering MT-PNPs as a ratiometric sensor for selective and accurate Hg2+ monitoring. A wide linear range (0.1-1471 mu M) and a low detection limit (95 nM) are obtained. This dual-signal opposite responses triggered by Hg2+ originate from the formation of MT-PNP-Hg2+ congeries via the multisite binding between S,N,O-containing groups of MT-PNPs and mercury. Meanwhile, target-induced aggregation renders an effective Hg2+ separation from contaminative aqueous media by MT-PNPs, which exhibits a satisfactory absorption efficiency of 90.42% within 50 min. Upon the simple Na2S treatment, the MT-PNPs can be regenerated and reused. This work thus delivers an applicable method for the ratiometric detection and effective removal of mercury with the novel nonconjugated PNPs, offering potential in tackling the problem of heavy metal ion pollution for environmental monitoring and remediation.