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

Abstract

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 Hg 2+ . A good linearity is obtained between I Rh6G /I QDs and Hg 2+ 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 Hg 2+ 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 Hg 2+ detection and removal in environmental, biological, and toxicological areas.

Mesoporous silica based recyclable probe for colorimetric detection and separation of ppb level Hg2+ from aqueous medium

“…A comparative study on recent silica based materials 20–23,35–40 for sensing and/or separation of mercury has been carried out. A summary of some of the important aspects of the materials has been given in supplementary information, Table S6.…”

“…In this respect, mesoporous silica based structures have drawn considerable interest as they can simultaneously detect as well as separate the metal ions 17–19 by virtue of the organic functional groups homogeneously anchored on their surface and large surface area with uniform pore size distribution. Multifunctional recyclable magnetic mesoporous silica 20 based on CdTe quantum dots and rhodamine-6G has been reported for ratiometric sensing, adsorption and removal of Hg 2+ ions. Thiol functionalized short channel 21 SBA-15 and hollow mesoporous silica microspheres with magnetic cores 22 have been used for the adsorption of Hg 2+ ions.…”

Dual-Emission Fluorescent Microspheres for the Detection of Biothiols and Hg2+

“…The higher concentration of Hg 2+ deviates from the linearity based on 3δ/m (δ is the standard deviation of the double-emitting fluorescent microsphere signal ( n = 7), m is the slope of the linear calibration chart), and the detection limit is 97 nM. Comparison of the present sensor with other existing Hg 2+ sensitive probes based on silica was presented in Table 1 [23,24,25,26,27,28]. The results showed the detection limits of our present sensor were comparable and even better than those of other sensors, and the advantage of ratiometric detection is greater.…”

Organically Functionalized Mesoporous SBA-15 Type Material Bearing Fluorescent Sites for Selective Detection of HgII from Aqueous Medium

“…So, organic fluorophore moieties bound at the surface of the mesoporous silicas have become an important research area for selective adsorption and sensing applications. 38−41 Thus, considerable research efforts have been devoted in developing novel sensor probes based on mesoporous SBA-15 to detect Hg and other heavy metals from water resources. 42−45…”

“…The mesoporous silicas can be surface-functionalized through different organic functional groups by grafting or co-condensation approaches so that the resulting material can bind different metal ions via strong coordination. So, organic fluorophore moieties bound at the surface of the mesoporous silicas have become an important research area for selective adsorption and sensing applications. − Thus, considerable research efforts have been devoted in developing novel sensor probes based on mesoporous SBA-15 to detect Hg and other heavy metals from water resources. − …”