Non-rare earth doped metal-organic framework for fluorescent detection of uranyl in real seawater

Abstract

Rare-earth doped fluorescent metal-organic frameworks (MOFs) are widely used for the fluorescence quenching detection of uranyl ions. However, few existing studies have developed red fluorescence-enhanced, non-rare-earth doped MOF probes with anti-background interference capabilities. Therefore, it is of great significance to develop a UO₂^2 + fluorescent probe with higher specificity and sensitivity, while maintaining long-wavelength fluorescence properties similar to those of rare-earth doped materials. Herein, we prepared a porphyrin-based MOF with nickel chloride hexahydrate as the nickel source, and tetrakis (4-carboxyphenyl) porphyrin as the organic ligand, called Ni-TCPP, which could be used as a fluorescence probe for simultaneous visual detection and removal of the common pollutant uranyl in seawater. Specifically, Ni-TCPP responds to ultra-low concentrations of uranyl ions (16.59 nM) and, through an efficient fluorescence "turn-on" mechanism, has become one of the most sensitive MOF-based fluorescent sensing materials. In addition, the material was demonstrated for the removal capability of uranyl for its suitable pore size and large surface areas. By merging the optical and adsorption properties of Ni-TCPP, we have creatively developed a dual-functional platform for sensing and removing uranyl in actual seawater samples, demonstrating significant potential for practical applications.