Simultaneous fluorescence response and adsorption of functionalized Fe3O4@SiO2 nanoparticles to Cd2+, Zn2+ and Cu2+

An available route was provided for simultaneous detection and effective adsorption toward Cd2+, Zn2+ and Cu2+. The magnetic Fe3O4@SiO2 nanoparticles were prepared and functionalized with N-(quinoline-8-yl)-2-(3-triethoxysilyl-propylamino)-acetamide (QTPA) by first using the "grafting from" method, which made the whole process of surface modification on Fe3O4@SiO2 nanoparticles simpler and more effective. The as-synthesized QTPA functionalized Fe3O4@SiO2 nanoparticles exhibited different fluorescence responses for Cd2+ (doderblue), Zn2+ (deepskyblue) and Cu2+ (tomato red) illuminated under a 365 nm UV light, while other ions, such as Ag+, Hg2+, Ni2+, Co2+, Mn2+, Pb2+, Cr3+ and Fe3+, gave no visible changes under identical experimental conditions. The eye-perceived fluorescent changes only toward Cd2+, Zn2+ and Cu2+ could serve as the available proofs for the qualitative analysis of the three cations. The UV-vis spectra results showed that the multifunctional nanoparticles exhibited fluorescence enhancements for Cd2+ and Zn2+, and fluorescence quenching for Cu2+. The adsorption experiments showed that the nanomaterial was a good candidate for selective removal and enrichment of Cd2+, Zn2+ and Cu2+, and had the high adsorption efficiency toward Cd2+ (95.29%), Zn2+ (92.37%), and Cu2+ (91.06%). Moreover, the functionalized composites had strong magnetic sensitivity, which could make them susceptible in an external magnetic field, and easy to separate from the solid and liquid phase. More specific to this work, simultaneous fluorescence determination of Cd2+, Cu2+, and Zn2+ by naked eye was proposed based on QTPA functionalized Fe3O4@SiO2 nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.