Recyclable Multifunctional Magnetic Mesoporous Silica Nanocomposite for Ratiometric Detection, Rapid Adsorption, and Efficient Removal of Hg(II)

In this paper, multifunctional inorganic–organic nanocomposites were fabricated through encapsulating CdTe quantum dots and Rhodamine 6G-deprived receptor into the nonporous and mesoporous shell of the magnetic mesoporous silica nanocomposites. The resultant nanomaterials display an obvious core–shell structure, superparamagnetic property, ordered mesoporous characteristics, and highly selective, sensitive, and regenerative ratiometric fluorescent sensing performance for determination of Hg2+. A good linearity is obtained between IRh6G/IQDs and Hg2+ concentration (0.7 to 90 × 10–8 mol·L–1), exhibiting a detection limit as low as 2.5 × 10–9 mol·L–1. Moreover, the multifunctional nanocomposites possess acceptable Hg2+ adsorption capacity and can be simply separated by magnet. Real water sample assays further verified its good mercury ion analysis and removal ability. Our results reveal that high sensitivity, selectivity, rapid adsorption, efficient removal ability, and good reusability as well as better accuracy can be simultaneously achieved by combining magnetic mesoporous silica nanocomposite with ratiometric fluorescence sensing properties than the traditional intensity-based fluorescence methods. This recyclable multifunctional hybrid nanostructure may have great potential for Hg2+ detection and removal in environmental, biological, and toxicological areas.