Covalent organic framework-based materials: Synthesis, modification, and application in environmental remediation

Covalent organic framework (COF) is a group of porous organic polymeric materials obtained from covalently attached organic building blocks. They exhibit positional control in two- or three-dimensional spaces through the predesigned and specified bonding of the monomer linkers. COFs are contemporary materials, and the recent identification of various synthesis and linking procedures has allowed their preparation with many advantageous properties and their usage in various applications. They can also be postsynthetically modified or converted to other materials of specific interest, thereby achieving materials with improved physical and chemical properties. COFs are considered as one of the most promising materials for applications in environmental remediation because of their ordered geometry, high porosity, functionality, high stability, and postsynthetic tunability in various physical and chemical forms. This review highlights the basic state-of-the-art in the advancement of stable COFs and their postsynthetic modification methods. The environmental remediation applications of COFs, which include adsorption, filtration, separation, catalysis, and sensing, will also be discussed in detail. Finally, the outcomes will be summarized and future directions will be discussed, indicating their promise for specialists in various research fields. (C) 2021 Elsevier B.V. All rights reserved.