Detection of Trace Amounts of Fe3+ and Cr6+ Ions Using a ZIF‑8 Fluorescent Sensor with High Selectivity and Fast Response

Abstract

While zeolitic imidazole framework (ZIF)-based materials have shown promising metal ion detection performances, they did not achieve the same results as for pure ZIFs. Here, a highly porous ZIF-8 material is synthesized using a chemical method under stirring at room temperature, and characterized in terms of crystallinity and chemical state. The resulting ZIF-8 is employed as a multifunctional uorescent sensor to detect Fe3+ and Cr6+ metal ions dissolved in water, exhibiting high luminescence with a broad wavelength band in the visible light region. The water-soluble metal ions are found to be very sensitive to a decrease in the luminescence intensity of ZIF-8, and can be detected at trace amounts with high selectivity. The detection limits of Fe3+ and Cr6+ ions are achieved to be 2.1 × 10–6 and 7.6 × 10–7 M, respectively. The intensity of luminescence decreases with increasing the concentration of both metal ions, thereby giving rise to the complete uo>rescence quenching with a very fast response time using Fe3+ and Cr6+ ion concentrations higher than 1.0 × 10–4 and 4.7 × 10–5 M, respectively. These results may pave the way for the utilization of pure ZIF materials in the development of highly ecient uorescent sensors in order to rapidly detect trace amounts of environmental pollutants.