Regenerable and Highly Stable Two-Dimensional Imine-Based Covalent Organic Framework for Simultaneous Rapid Detection and Adsorption of Cu<sup>2+</sup> Ions
Yaoxiao Zhao, Yulong Li, Weixing Chen, Xilang Jin
Abstract
The development of efficient fluorescent probes and adsorbents for detecting and removing Cu 2+, which pose potential environmental and health risks, is a highly active area of research. However, achieving simultaneously improved fluorescence detection efficiency and enhanced adsorption capacity in a single porous probe remains a significant challenge. In this study, we successfully synthesized a two-dimensional imine-based TAP-COF using 2,4,6-triformylphloroglucinol and tri(4-aminophenyl)amine as raw materials. TAP-COF exhibited excellent properties, including a large specific surface area of 685.65 m 2 ·g –1, exceptional thermal stability (>440 °C), chemical stability, temporal stability, and recyclability. Fluorescence testing revealed that TAP-COF exhibited remarkable specificity and high sensitivity for detecting Cu 2+ . The fluorescence mechanism, in which the excited state intramolecular proton transfer was impeded by the interaction of Cu 2+ with C═O and C–N bonds on TAP-COF upon the addition of Cu 2+, was further elucidated through experimental and theoretical methods. Furthermore, the adsorption capacity of TAP-COF toward Cu 2+ was investigated, confirming the excellence of TAP-COF as a fluorescent probe and adsorbent for the specific detection and removal of Cu 2+ . This work holds significant implications for improving environmental and human health concerns associated with Cu 2+ contamination.