Carbon dot-functionalized macroporous adsorption resin for bifunctional ultra-sensitive detection and fast removal of iron(III) ions.

Heavy metal pollution has spread around the world with the development of industry, posing a major threat to human health. It is urgent to design and fabricate bifunctional materials for detection and adsorption of heavy metal ions. Herein, poly(glycidyl methacrylate--ethylene glycol dimethacrylate) microspheres, a kind of common macroporous adsorption resin (MAR), were employed as the matrix, and carbon dots (CDs) with excellent optical properties were grafted onto the surface of MAR by surface-initiated atom transfer radical polymerization (SI-ATRP) and photo-initiated "thiol-yne" click chemistry. The synthesized MAR@poly(PA)@CD could produce fluorescence quenching with Fe. A simple fluorescence spectrometric method for detection of Fe was established. The fluorescence intensity of MAR@poly(PA)@CD decreased linearly with the concentration of Fe in the range of 0-70 nmol L, with a limit of detection (LOD) of 6.6 nmol L, which had the potential for trace detection. In addition, after SI-ATRP modification, many adsorption sites were generated on the surface of MAR, and the adsorption capacity for Fe was 23.8 mg g. Isothermal and kinetic adsorption experiments were more consistent with the Langmuir model ( = 0.9992) and pseudo-second-order model ( = 0.9902), indicating that the adsorption was monolayer adsorption and chemical adsorption, respectively. MAR@poly(PA)@CD with dual functions of detecting and adsorbing Fe was successfully prepared, showing great application prospects in the environmental field.