Covalent Organic Frameworks as Next-Generation Adsorbents for Emerging Contaminants

The escalating global water pollution crisis is significantly driven by industria waste discharges, which constitute a major pollution source. Covalent organic frameworks (COFs), with their tailorable porosity, exceptional stability, and tunable functional sites, have emerged as a transformative platform for addressing contaminated water resources. Given the vast and diverse scope of research in this field, a timely summary of current developments and an exploration of emerging frontiers are essential. However, existing reviews suffer from reliance on outdated literature and lack of timely updates. In response, this review systematically consolidates the latest advancements in the application of COFs for the adsorption of three key classes of pollutants, 1) heavy metal ions (including radioactive species) such as Pb^{2 +}, Cd^{2 +}, and UO₂ ^{2 +}, 2) organic pollutants (e.g., dyes, pharmaceuticals, and antibiotics), and 3) radioactive iodine species. Beyond summarizing performance, we critically analyze the underlying structure-adsorption mechanism relationships that enable their high efficiency. Nevertheless, critical challenges-such as selectivity in complex system, material generality, and practical engineering feasibility persist for practical industrial applications. The future development trajectory is anticipated to concentrate on intelligent responsive design, multifunctional integration, enhanced mass transport, and engineering-oriented material architecture to address the aforementioned challenges and meet requirements of practical applications.