Hydrophilic P(Am-CD-AMPS) microgel for visual detection and removal metal ions in aqueous solution

Heavy metal are harmful to the mankind and difficult to observe in water, so it is necessary for the detection and removal of metal ions. Carbon dots (CDs) are novel fluorescent materials for detecting metal ions and their modified nanocomposites have great potential for water treatment applications. Our research is developing a dual material of detecting and adsorbing metal ions based on poly acrylamide-co-CD-co-2-acrylamido-2-methylpropanesulfonic acid (poly (Am-CD-AMPS)) by inverse miniemulsion polymerization. Firstly, CDs were functionalized with glycidyl methacrylate (GMA) to obtain double bond which can be stably immobilized into the microgels network during the polymerization. The prepared poly (Am-CD-AMPS) microgels demonstrated the blue fluorescent property and excitation-dependent behavior under UV light and Fluorescence spectrophotometer. The microgels had sensitivity toward Hg 2+ , Fe 3+ and Cu 2+ and detection limit as low as 2.3 nM, 3.2 μM and 1.3 μM. Meanwhile, poly (Am-CD-AMPS) microgels had adsorption capacity of 102.13 mg·g −1 and 85.00 mg·g −1 toward to Fe 3+ and Cu 2+ , and detailing of the possible mechanistic insight into the ion adsorption was also discussed. Reusability measurements showed that the synthesized microgels had the better stability in application of detecting and adsorbing metal ions.