Fusion of materials with directional-selection and family-selection properties to prepare covalent organic framework composite with superior selective adsorption performance

Materials with high adsorption properties and high selectivity are ideal adsorbents for the application of adsorption. Herein, by using tetrabrombisphenol A (TBr-BPA) as the template, a novel COF-based composite (SiO2@F-COF@MIP) with directional selectivity and three-dimensional spatial selectivity was developed for the first time. Superior selective adsorption effects of TBr-BPA and family-similar compound (tetrachlorbisphenol, TCl-BPA) can be achieved by using composite as the adsorbent. Firstly, to verify the performance of the composite, the selective adsorption effects of F-COF, SiO2-NH2, SiO2-NH2@F-COF and SiO2@F-COF@MIP on TBr-BPA, TCl-BPA and competing compounds were investigated and compared. Results showed that SiO2@F-COF@MIP had extremely high selective adsorption capacities for TBr-BPA and TCl-BPA with the maximal adsorption capacities of 653.2 and 158.8 mg·g−1, respectively. Secondly, by using computer simulation and experiments analysis, the mechanisms of SiO2@F-COF@MIP for the highly selective adsorption were explored. Results revealed the selective adsorption of TBr-BPA on SiO2@F-COF@MIP was mainly based on halogen bond interaction, three-dimensional space selectivity effect coupled with hydrogen bond and electrostatic interactions. The selective adsorption of TCl-BPA was mainly based on three-dimensional space selectivity, hydrogen bond and electrostatic interactions. Finally, SiO2@F-COF@MIP was used as the adsorbent for the enrichment of TBr-BPA and TCl-BPA in actual water and fish samples, and satisfactory recoveries were obtained, proving that SiO2@F-COF@MIP has great application prospect in high selective enrichment.