Hg(II)
contamination in water resources is one of the major health
issues in keeping the purity standard of the municipal water supply.
Herein, we report a new mesoporous sensor probe material SBA-ABZ-PEA
having a 2D-hexagonally ordered mesoporous framework bearing covalently
bonded fluorescent sites, and this has been synthesized through a
two-step post-synthesis grafting route. A pure silica mesoporous SBA-15
material has been functionalized with (3-chloropropyl)triethoxysilane
(ClPTES) to obtain chloro-functionalized SBA-15, which was further
reacted with 4-aminobenzaldehyde followed by treatment
with 2-(2-pyridyl)-ethylamine resulting in functionalized 2D-hexagonal
mesoporous sensor probe SBA-ABZ-PEA. Small angle PXRD, N2 adsorption/desorption, HRTEM, TGA, and FT-IR studies have been carried
out to characterize these materials. Our experimental results suggested
successful grafting of the organic moiety on the SBA-15 surface along
with preservation of mesoporosity throughout the grafting process.
Photoluminescence measurements were carried out in the aqueous suspension
of SBA-ABZ-PEA in the presence of different metal cations, like NaI, MgII, AlIII, KI, CaII, MnII, CoII, CuII, ZnII, CdII, PbII, and HgII.
This result revealed that, among the various metal-ions, the emission
intensity of the mesoporous sensing probe material SBA-ABZ-PEA has
been dramatically quenched in the presence of the HgII ion.
To check the sensitivity of the sensor probe, the fluorescence emission
was also studied in the presence of different concentrations of HgII ions. A perfect linear plot between the concentrations of
HgII ions in the aqueous medium with their corresponding
fluorescence intensities with a detection limit of 1.2 × 10–6 M has been observed.