Selection of appropriate pore size covalent organic frameworks for efficient extraction bisphenol compounds in water and food samples.

Covalent organic frameworks (COFs) with larger pore sizes will exhibit greater bisphenol adsorption capacity and faster adsorption rates than COFs with smaller pore sizes. Different por size will offer different binding affinity between magnetic COFs and BPs. Herein, four different pore sizes of magnetic COFs were prepared by grafting trialdehyde monomers with different numbers of benzene rings. The Fe3O4@TBrAPT-Dt-COF (3.0 nm) exhibited the best extraction effect towards BPs, which can be attributed to the larger pore of magnetic COFs eliminated the diffusion obstruction associated with small-pore molecules, leading to the enhanced absorption (141 mg g-1). Further increase in pore size weakened the binding affinity of magnetic COFs (32 mg g-1). The Fe3O4@TBrAPT-Dt-COF achieved 8 recycles in the process of absorption and desorption. This work first predictes the appropriate magnetic COFs pore size for BPs extraction and concurrently presents a new strategy for COF design for BPs removal.