Functionalized Cubic Mesoporous Silica as a Non-Chemodosimetric Fluorescence Probe and Adsorbent for Selective Detection and Removal of Bisulfite Anions along with Toxic Metal Ions

Dual signaling and remediation systems for detection and adsorption of toxic analytes have gained more attention over sensory probes only. However, most of the sensors for bisulfites are chemodosimetric probes, which are irreversible and having drawbacks of absolute selectivity, recyclability, and solubility in a pure aqueous system. To address above drawbacks a new non-chemodosimetric probe material with a strong hydrogen bonding pocket for bisulfites is developed. Synthesis of cubic mesoporous silica by a modified Stober process followed by functionalization with 2,2'-(((((3-(triethoxysilyl) propyl) azanediyl) bis(methylene)) bis(2,1-phenylene)) bis(oxy)) bis(N-(4-((E)phenyldiazenyl) phenyl) acetamide) (AZOL) has given a fluorogenic silica probe material SiO2@AZOL. This material shows selectivity toward bisulfite anion (limit of detection (LOD): 64 ppb) and Hg2+, Cd2+, Cu2+, and Zn2+ cations (LOD: 126, 95, 14, and 27 ppb, respectively) among various analytes. The adsorption studies for these toxic analytes (HSO3,- Hg2+, Cd2+, Cu2+, and Zn2+) show an extraction efficiency of around 99% and adsorption capacities of 873, 630, 633, 260, and 412 mg g(-1), respectively. Spectroscopic studies along with adsorption, striping, and regeneration studies reveal that this material is a recyclable sensory cum adsorbent material for these toxic analytes. Moreover, this material can be used as a sensitive probe material for determination of HSO3- levels in various sugar samples.