Recent advances in analytical sensing detection of heavy metal ions based on covalent organic frameworks nanocomposites

Sensitive and selective determination of heavy metal ions is an important research. Analytical detection techniques that are based on nanomaterials have shown advantages of simplicity, sensitivity, and low cost. Covalent organic frameworks (COFs) are a newly emerging class of crystalline porous organic frameworks that are connected by organic monomers via covalent bonds. Currently, COFs nanocomposites have been extended to analytical sensing applications, especially the construction of sensors benefiting from their structural tailorability and diversity, large surface area, intrinsic stability, and tunable functionality. This review mainly summarizes the recent advances in COFs nanocomposites-based sensors for chemical detection of heavy metal ions. The unique advantages of COFs for chemical sensing are highlighted. Then, different types of chemical sensors for heavy metal ions based on fluorescence, colorimetry and electrochemistry are reviewed. Simultaneously, the analytical performances are summarized. Finally, a summary of the current achievements is given and further future research directions are outlined.