Simultaneous fluorescence response and adsorption of functionalized Fe_3O_4@SiO_2 nanoparticles to Cd~(2+), Zn~(2+) and Cu~(2+)

摘要

An available route was provided for simultaneous detection and effective adsorption toward Cd~(2+), Zn~(2+) and Cu~(2+). The magnetic Fe_3O_4@SiO_2 nanoparticles were prepared and functionalized with N-(quinoline8-yl)-2-(3-triethoxysilyl-propylamino)-acetamide (QTPA) by first using the "grafting from" method, which made the whole process of surface modification on Fe_3O_4@SiO_2 nanoparticles simpler and more effective. The as-synthesized QTPA functionalized Fe_3O_4@SiO_2 nanoparticles exhibited different fluorescence responses for Cd~(2+) (doderblue), Zn~(2+) (deepskyblue) and Cu~(2+) (tomato red) illuminated under a 365 nm UV light, while other ions, such as Ag~+, Hg~(2+), Ni~(2+), Co~(2+), Mn~(2+), Pb~(2+), Cr~(3+) and Fe~(3+), gave no visible changes under identical experimental conditions. The eye-perceived fluorescent changes only toward Cd~(2+), Zn~(2+) and Cu~(2+) 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 Cd~(2+) and Zn~(2+), and fluorescence quenching for Cu~(2+). The adsorption experiments showed that the nanomaterial was a good candidate for selective removal and enrichment of Cd~(2+), Zn~(2+) and Cu~(2+), and had the high adsorption efficiency toward Cd~(2+) (95.29%), Zn~(2+) (92.37%), and Cu~(2+) (91.06%). Moreover, the functionalized composites had strong magnetic sensitivity, which could make them susceptible in an