A reusable bifunctional fluorescent sensor for the detection and removal of silver ions in aqueous solutions

In this work, a novel bifunctional fluorescent sensor (FQ) was developed for simultaneous detection and removal of Ag⁺ in aqueous solutions by grafting a naphthalimide-based fluorescent probe onto the surface of the mesoporous silica nanoparticles. FQ exhibited good selectivity towards Ag⁺ in water samples, and showed 2.5-fold enhancement of fluorescence intensity with the addition of Ag⁺. Meanwhile, FQ showed a very good linearity at a low concentration of Ag⁺ with a detection limit of 7.2 × 10⁻⁶ M. In addition, FQ can also serve as an adsorbent for the removal of Ag⁺ in water samples with the maximal adsorption capacity of 14.8 mg g⁻¹. FQ can be regenerated easily by modulating the pH value of the aqueous solution, and can be recycled at least eight times. All results demonstrate that FQ has potential applications for the detection and removal of Ag⁺ in aqueous samples.