Controllable synthesis of bifunctional magnetic carbon dots for rapid fluorescent detection and reversible removal of Hg 2 .

Mercury is one of the most toxic heavy metals, whose identification and separation are crucial for environmental remediation. Till now, it remains a significant challenge upon simultaneous detection and removal of Hg ²⁺ . Herein, bifunctional probe magnetic carbon dots were synthesized and optimized via systematic structure manipulation of the carbon and iron precursors towards fluorescence, Hg ²⁺ adsorption and magnetic separation. The probe exhibited blue emission at 440 nm with high quantum yield of 55 % and a high paramagnetism with the saturation magnetization value of 22.70 emu/g. Furthermore, the fluorescent detection of Hg ²⁺ with limit of 5.40 nM and high selectivity were achieved through surface structure manipulation with moderate -NH ₂ , -SH and Fe contents. As a result, the magnetic removal of Hg ²⁺ was consecutively effectuated with high removal efficiency of 98.30 %. The detection and recovery of Hg ²⁺ in real samples were further verified and demonstrated the excellent environmental tolerance of probe. The reusability was viable with recycling at least three turns by external magnet. This work not only provides a promising approach for simultaneous detection and removal of heavy metal pollution, but also provides an excellent example as a versatile platform for multifunction integration via the structure manipulation for other applications.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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