Multifunctional Binding Strategy on Non-Conjugated 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 to address heavy metal contamination in environmental science. Herein, novel non-conjugated 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 μM) and a low detection limit (95 nM) are obtained. This dual-signal opposite responses triggered by Hg2+ originate from the formation of MT-PNPs-Hg2+ congeries via the multi-site 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 exhibit 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 non-conjugated PNPs, offering potential in tackling the problem of heavy metal ions pollution for environmental monitoring and remediation.