Design and fabrication of boric acid functionalized hierarchical porous metal-organic frameworks for specific removal of cis-diol-containing compounds from aqueous solution

Hierarchical porous metal-organic frameworks (HP-MOFs) has received extensive focus on adsorption field owing to its sizeable porosity and considerable surface area. However, to further improve the adsorption capacity, recognition of targets based on specific affinity is one of the most effective approaches. Herein, through the methods of etching acid-labile Zn-MOFs and post-modification with boric acid functional group, we synthesized novel boronate affinity HP-MOFs (BA-HP-UiO-66) as a specific adsorbent for large cis-diol-containing molecules. It was found that the average pore diameter of BA-HP-UiO-66 expanded from 0.85 nm of original UiO-66-NH2 to 3.42 nm with surface area of 630.91 m2·g−1. Teicoplanin, a glycopeptide antibiotic with cis-diol structure, was selected as a large size molecular model to evaluate the specific adsorption performance of BA-HP-UiO-66. Due to the large pore size and boronate affinity, the resultant BA-HP-UiO-66 performed much better in the adsorption of teicoplanin than microporous UiO-66-NH2. According to Langmuir isotherm model, the saturated adsorption capacity of BA-HP-UiO-66 on teicoplanin was up to 526.31 mg·g−1. This work demonstrated that BA-HP-UiO-66 has a good application prospect in environmental remediation, particularly in the removal of large size molecules.