Covalent organic frameworks@chitosan/β-cyclodextrin aerogels for synergistically enhanced bisphenol A adsorption

A TpPa-1@CS/β-CD aerogel is fabricated via freeze-drying and in-situ self-assembly. • The composite aerogel exhibits exceptional BPA adsorption capacity of 163.40 mg/g. • The TpPa-1@CS/β-CD aerogel is ultra-lightweight, elastic and regenerable. • After treatment with the aerogel, the COD of BPA meets the emission standard. The presence of bisphenol A (BPA), a significant industrial chemical, in aquatic environments poses persistent ecological risks and requires effective mitigation. Herein, a novel composite aerogel, TpPa-1@CS/β-CD, was fabricated by integrating freeze-drying and in-situ self-assembly. The TpPa-1 COF and chitosan/β-cyclodextrin (CS/β-CD) matrix provide abundant sites for synergistic BPA removal. The adsorption mechanism involves hydrogen bonding between the composite’s N- and O-containing groups and BPA hydroxyls, π-π stacking between BPA benzene rings and TpPa-1 conjugated frameworks, and hydrophobic inclusion in β-CD and TpPa-1 cavities. The aerogel exhibits a high BPA adsorption capacity of 163.40 mg/g, with kinetics and isotherm fitting the pseudo-second-order and Freundlich models, respectively. It also demonstrates ultra-lightweight, mechanical elasticity, and satisfactory regeneration. In dynamic filtration, the aerogel achieved 95.85% BPA removal at 20 mg/L. When applied to raw sewage, the aerogel achieved a BPA removal efficiency of 79.49% and reduced the COD from 174.18 to 55.99 mg/L, meeting the GB 31572–2015 emission standard. This study presents a valuable strategy for in-situ preparation of COF-based composite aerogels as high-performance adsorbents for advanced wastewater treatment. Download: Download high-res image (243KB) Download: Download full-size image