Atomically dispersed Eu(III) sites in natural deep eutectic solvents based fluorescent probe efficient identification of Fe3+ and Cu2+ in wastewater

Heavy metal ions in wastewater have brought serious environmental pollution. To improve the detection efficiency, it is important to find useful fluorescent probes. The emerging green natural deep eutectic solvents (NADESs) offer attractive option for "green" detection for its good biocompatibility, easy preparation, and high sensitivity. In this study, a multi-functionalized fluorescent probe with atomically dispersed EuCl3.6H(2)O in amino acid-based NADESs (L-Glutamic acid/Glycerol, L-Glu/Gly) was synthesized by metal-ligand coordination interactions with a mass ratio of 15:1. Combined with the NADESs and rare earth metal, the L-Glu/Gly/EuCl3.6H(2)O could form the amino site and Eu2+ site fluorescent centers. Under the excitation wavelength of 370 nm, it had dual emission peaks at 425 nm and 470 nm with efficient resonance energy transfer. The stable optoelectronic properties of L-Glu/Gly/EuCl3.6H(2)O under external factors, such as mass ratio (13,1 to 18:1), temperature (30-50 degrees C), pH (1 to 14) and storage time ( >42 days), approved L-Glu/Gly/EuCl3.6H(2)O an excellent fluorescence probe. In the application of water-quality monitoring, Fe3+ and Cu2+ could react with L-Glu/Gly/EuCl3.6H(2)O in different reactive patterns. The blue fluorescence was quenched by Fe3+ and enhanced by Cu2+, thus metal ions could be distinguished with high sensitivity. The detective process was determined and the fluorescent mechanism was also proposed. L-Glu/Gly/EuCl3.6H(2)O fluorescent probe was demonstrated to be an efficient fluorescent probe for metal detection avoiding the hydrothermal process, and the cumbersome of ilter, dialysis, freeze drying. (C) 2019 Elsevier B.V. All rights reserved.