SBA-15 Functionalized with Naphthalene Derivative for Selective Optical Sensing of Cr2O7(2-) in Water

A novel organic-inorganic hybrid optical sensor (NUS) was designed and prepared in two steps: the grafting of 3-(isocyanatopropyl)trimethoxysilane onto the surface of SBA-15, and then the attachment of naphthalene-1-amine. The obtained materials were characterized using low-angle XRD, N2 adsorption-desorption, TGA, FT-IR, and TEM techniques. A fluorescence study revealed that the NUS was a highly selective optical sensor for the detection of Cr2O7(2-) among various anions, including F(-), I(-), Cl(-), Br(-), CO3(2-), HCO3(-), NO3(-), H2PO4(-), CH3COO(-), and NO2(-) with a good linearity between the fluorescence intensity and the concentration of Cr2O7(2-) as well as a detection limit of 1.2 × 10(-7) M in a 100% aqueous medium. Moreover, the applicability of real samples of the sensor is also discussed.