Tailoring multifunctional gel for sensitive naked-eye and fluorescence dual-mode detection and effective adsorption of cadmium(Ⅱ) and lead(Ⅱ) ions in water

Water contamination caused by toxic cadmium (Cd2+) and lead (Pb2+) has become a global environmental issue, making it imperative to develop versatile functional materials for their monitoring and remediation. However, developing a versatile platform for the simultaneous sensitive multiple signal detection and effective removal of Cd2+ and Pb2+ remains a formidable challenge. Herein, a multifunctional gel for sensitive detection and effective adsorption of Cd2+ and Pb2+ is facilely constructed by integrating glycidyl methacrylate functionalized fluorescent graphene quantum dots and N, N'-methylenebisacrylamide co-crosslinked poly(thioctic acid) with physical crosslinked fluorescent gelatin. Interestingly, the gel shows cyan to chartreuse/violet fluorescence color change and fluorescent turn-on/turn-off switch after adsorbing Cd2+/Pb2+, thus for the first time simultaneous sensitive naked-eye and fluorescence dual-mode detection of Cd2+ and Pb2+ are achieved in a broad liner range (0.02–0.24 μmol). Meanwhile, the gel can effectively absorb Cd2+ and Pb2+ in water with maximum adsorption capacities of 194.553 and 259.067 mg g−1, respectively, surpassing previously reported adsorbents. Additionally, the gel exhibits excellent self-healing capability, reprocessability, biodegradability and biocompatibility, which can prolong its service life and prevent secondary contamination in practical applications. This study not only develops a versatile platform for the simultaneous sensitive detection and effective removal of Cd2+ and Pb2+, but also provides an innovative design strategy for inspiring future research to fabricate multifunctional materials for monitoring and decontamination heavy metal polluted water.