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

Luna Paul; Somali Mukherjee; Sauvik Chatterjee; Asim Bhaumik; Debasis Das

doi:10.1021/acsomega.9b02631

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

ACS Omega. 2019 Oct 14;4(18):17857-17863. doi: 10.1021/acsomega.9b02631. eCollection 2019 Oct 29.

Authors

Luna Paul¹, Somali Mukherjee¹, Sauvik Chatterjee², Asim Bhaumik², Debasis Das¹

Affiliations

¹ Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India.
² School of Materials Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S. C. Mullick Road, Jadavpur 700 032, India.

Abstract

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 Na^I, Mg^II, Al^III, K^I, Ca^II, Mn^II, Co^II, Cu^II, Zn^II, Cd^II, Pb^II, and Hg^II. 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 Hg^II ion. To check the sensitivity of the sensor probe, the fluorescence emission was also studied in the presence of different concentrations of Hg^II ions. A perfect linear plot between the concentrations of Hg^II ions in the aqueous medium with their corresponding fluorescence intensities with a detection limit of 1.2 × 10^-6 M has been observed.