Detection and sorption of heavy metal ions in aqueous media using Zn-based luminescent metal-organic framework

Abstract

In this study, we present the synthesis and comprehensive characterisation of a novel, luminescent Metal-Organic Framework (MOF) denoted as PUC7, derived from Zn(NO3)2·6H2O, 1,2-di(4-pyridyl)ethylene, and 2-amino-terephthalic acid through solvothermal method. The PUC7 was successfully characterised using many techniques, including single crystal X-ray diffraction, powder X-ray diffraction, FTIR spectroscopy, BET surface area analysis, FESEM imaging, XPS, UV–visible spectroscopy, and zeta potential measurements. Remarkably, PUC7 exhibited high luminescence properties and water stability. The luminescence properties were utilised for the detection of heavy metal ions. Consequently, PUC7 displayed exceptional selectivity and sensitivity towards W6+ and V5+, with impressively low detection limits of 0.17 μM and 0.22 μM, along with high quenching constant values of 2.5 × 105 M−1 and 1.1 × 105 M−1, respectively. Additionally, we explored PUC7′s proficiency in removing W6+ and V5+ ions from aqueous solution, revealing maximum adsorption efficiencies of 476.2 mg/g and 460.8 mg/g, respectively, fitting well with the Langmuir adsorption model and exhibiting second-order kinetics. Encouragingly, PUC7 demonstrated reusability for up to five cycles in removing W6+ and V5+ ions. Altogether, this research underscores the potential of PUC7 as a versatile and promising tool for efficiently detecting and removing W6+ and V5+ ions from water, with implications for environmental remediation and water purification applications.