Highly fluorescent nickel based metal organic framework for enhanced sensing of Fe3+ and Cr2O72− ions

Abstract

Heavy metal contamination has sparked widespread concern among the populace. The significant issues necessitate the creation of high-performance fluorescent pigments that can identify harmful elements in water. The present study deals with metal organic framework [MOF] based on nickel [Ni-BDC MOF]. The Ni-BDC MOF was prepared by facile solvothermal method using nickel nitrate hexahydrate and terephthalic acid ligand as precursors. The MOF was characterized by various techniques in order to examine the crystal, morphological, structural, composition, thermal and optical properties. The detailed characterizations revealed that the synthesized Ni-BDC MOF are well-crystalline with high purity and possessing 3D rhombohedral microcrystals with rough surface. The MOF demonstrate good luminescence performance and excellent water stability. According to the Stern Volmer plot, the tests set up under optimized conditions demonstrate a linear correlation between the fluorescence intensity and concentration of both ions, i.e. Fe3+, and Cr2O72− ions. The linear range and detection limit for Fe3+ and Cr2O72− were found to be 0–1.4 nM and 0.159 nM, and 0–1 nM and 0.120 nM, respectively. The mechanisms for the selective detection of cations and anions were also explored. The recyclability for the prepared MOF was checked up to five cycles which showed excellent stability with just a slight reduction in efficiency. The constructed sensor was also used to assess the presence of Fe3+ and Cr2O72− ions in actual water samples. The results of the different experiments revealed that the prepared MOF is a good material for detecting Fe3+ and Cr2O72− ions.