Amine-decorated zirconium-based metal-organic framework for ultrafast detection of 2, 4, 6-trinitrophenol in aqueous medium

Abstract

Abstract An amine-decorated zirconium-based metal–organic framework (MOF, coded as UiO-66-NH2) with rod shaped morphology has been solvothermally synthesized using low-cost and easily available 2-aminoterephthalic acid as an organic linker. The crystallinity of the synthesized MOF material has been confirmed by sharp PXRD diffraction pattern. Photoluminescent studies showed that the UiO-66-NH2 features a strong fluorescent behaviour when dispersed in water, which could be used as a highly selective and sensitive sensor for detection of trace amount of 2,4,6-trinitrophenol (TNP), even in coexistence with other potentially competitive nitroaromatic analytes. High value of Stern-Volmer quenching constant Ksv (1.106 x 105 M-1), photoluminescent quenching efficiency (97.8%) and lower detection limit (0.95 μM/217ng mL-1) ascertained extraordinary sensitivity of developed UiO-66-NH2 for TNP. Density functional theory (DFT) calculations and electrostatic interactions (i.e. ionic interaction, H-bonding and π-π interaction) indicated that electron and energy transfer processes play a key role in the turn-off quenching response of UiO-66-NH2 sensor towards TNP.