Hybrid Nanomaterials as Effective Multifunctional Fluorescent Chemosensor for Sensitive and Selective Detection of Toxic Metal Ions

Abstract

Heavy metal ions are an extremely toxic and non-biodegradable contaminant of natural resources. Hence, a special concern is required to detect the occurrence of heavy metal ions in the aqueous system. This thesis consists of the nanomaterials-based hybrid sensor for rapid, precise and reliable recognition of heavy metal ions. The design strategies of nanomaterials based hybrid sensor are classified on the basis of nanomaterials, fluorophore, and organic receptors. newlineThe first segment of this thesis expresses the design in the magnetic core-shell fibrous silica nanocomposite and fabrication of the fluorescent probe, which is special interest in chemosensor for sensitive analysis of toxic heavy metal ions. The multifunctional core-shell magnetic fibrous silica nanocomposite (Fe3O4/MnO2/SiO2/KCC-1) was covalently grafted with rhodamine-B derivatives (Rh-B/KCC-1) as efficient hybrid sensor-I for sensing Cu(II) ions in aqueous medium. The hybrid sensor remained colorless and non-fluorescence. Upon addition of Cu(II) ions the sensing system turn-on bright pink color and enhanced fluorescence by spirolactam ring open in rhodamine-B derivatives. The sensitivity and selectivity of hybrid sensor-I was evaluated for analyzing Cu(II) ions in the existence of competitive metal ions, it is observed that good linearity in a concentration range of 5-70x10-4 M with a lower detection limit of 12.3x10-8 M. The hybrid sensor-II describes the magnetic fibrous silica (CoFe2O4/SiO2/KCC-1) effectively functionalized with pyrene-based derivatives as a hybrid chemosensor for the detection of Hg(II) ions newline