A review of covalent organic frameworks for metal ion fluorescence sensing

The concentration of metallic elements is closely associated with overall health. However, the discharge of untreated industrial wastewater can lead to metal-containing pollutants entering the human body through the food chain, disrupting the organism's homeostasis and posing a risk to human health. Covalent organic framework materials (COFs) have emerged as a novel porous material for detecting or adsorbing metal ions due to their unique pore structure, topological structure and flexible design. This paper summarizes the role, toxicity, and sources of metal ions related to human health, as well as the design, synthesis and performance of COFs fluorescent materials for detecting these elements. The interaction mechanism of different fluorescent COFs and metal ions are discussed. Additionally, the remaining challenges and prospects of COFs fluorescence sensors are provided. We believe this review will be useful in directing the development of fluorescent COFs towards metal ions.