Design and fabrication of boric acid functionalized covalent organic framework with sea urchin-like structure and its application for efficient enrichment of bisphenols.

The morphology and functional groups of materials have equally important effects on their properties. In this paper, a boric acid functionalized covalent organic framework with sea urchin-like structure (SU-COF-V-B(OH)2, where V denotes the vinyl groups derived from 2,5-divinylterephthalaldehyde) was prepared as a solid phase extraction (SPE) sorbent for bisphenols (BPs). The unique morphology provided enhanced analyte capacity, delivering 1.15-1.49 times higher enrichment than the solid spherical material. The prepared sorbent showed high removal performance (536.77 ± 37.04-833.69 ± 47.52 mg g-1). Binding energy calculations revealed the relative adsorption affinity of BPs at different sites, and together with Hirshfeld surface analysis and 2D fingerprint plots, the atomic-level interaction contributions between SU-COF-V-B(OH)2 and BPs were further elucidated. Moreover, a new detection method was established by SPE-high-performance liquid chromatography-diode array basing on SU-COF-V-B(OH)2, and exhibited the wide linear range (0.10-200 ng mL-1) and low detection limits (0.02-0.04 ng mL-1). The established method had been successfully used for detection of BPs in tap water and milk samples with satisfactory recoveries (80.1-111.8%). The material showed potential for pollutant removal and enrichment detection, with broader applications of sea urchin-like COFs expected in the future.