Sodium alginate/mesoporous silica composite hydrogel with AIE characteristics for sensitive detection and efficient capture of Fe3.

The development of integrated platform for the simultaneous detection and removal of heavy metal ions remains critical challenge in environmental monitoring. Herein, tetraphenylethylene-modified mesoporous silica nanoparticles (MSN-TPE) were fabricated via Schiff base reaction, and then incorporated into sodium alginate (SA) hydrogel for simultaneous detection and adsorption of Fe3+. The as-prepared hydrogel and MSN-TPE probe exhibited strong aggregation-induced emission (AIE) fluorescence, excellent stability against long-term storage, varied pH and temperatures. The hydrogel achieved sensitive and selective fluorescence quenching response to Fe3+, with a detection limit as low as 0.460 μM. Thanks to its porous network structure and abundant active sites, the hydrogel also demonstrated significant adsorption capacity for Fe3+, with the maximum theoretical adsorption capacity of 383.06 mg/g. Mechanism analysis indicated that Fe3+ quenched the fluorescence of probe through static quenching, and the adsorption process was mainly driven by the coordination and electrostatic interactions between Fe3+ and the nitrogen/oxygen functional groups in hydrogel. Combined with simple preparation and excellent anti-interference ability, this dual-functional hydrogel shows broad application prospects in water quality monitoring and heavy metal purification.