COF-Based Composites: Extraordinary Removal Performance for Heavy Metals and Radionuclides from Aqueous Solutions

Covalent-organic-framework-based composites (COF-based composites) are novel functional materials constructed by combining COFs and various organic/inorganic materials, which usually exhibit more advantageous physicochemical properties, stability, selectivity, and pollutant removal performance compared with pristine COFs. In this review, we highlighted the detailed categories and the recent advances of binary and ternary COF-based composites. In particular, the progress of COF-based composites for the efficient removal of heavy metals and radionuclides is comprehensively summarized. By comparing the performance with other materials, we found that the functional materials make the composites stand out. In addition, the technologies to investigate the internal mechanism of pollutants removed by COF-based composites, mainly including characterization analysis and theoretical calculations, are discussed and summarized, providing the direction for in-depth understanding of COF-based composites. According to the discussion above, the opportunities and challenges of COF-based composites in the treatment of heavy metals and radionuclides are summarized and prospected. Through this review, we desire to raise the awareness of COF-based composites and advance further studies in this field by proposing the potential research directions and applications.