Metal-Polyphenol Imprinted Hybrid Chitosan Aerogel with Enhanced Selective Recognition and Adsorption toward Phenol

Conventional powder-based molecularly imprinted polymers for phenol separation suffer from poor selectivity, limited adsorption capacity, and complicated solid–liquid separation processes. Herein, a metal-polyphenol imprinted hybrid chitosan aerogel (TA@CZIF-8/CSA) was constructed by integrating a tannic acid-copper imprinted layer with a hierarchically porous carbonized ZIF-8/chitosan aerogel matrix. The metal-polyphenol imprinted layer provides abundant phenol-specific recognition sites, while the hybrid aerogel framework facilitates mass transfer and enables solid–liquid separation. Static adsorption experiments demonstrated that TA@CZIF-8/CSA exhibits a high phenol adsorption capacity of 276.5 mg g–1 at pH 7.0 and 298 K, reaching adsorption equilibrium within 30 min. The relative selectivity factors toward structurally analogous compounds, namely hydroquinone and p-tert-butylphenol, were 11.26 and 13.83, respectively. Moreover, the monolithic aerogel retained 92% of its initial adsorption capacity after eight regeneration cycles, indicating recyclability. This study provides a promising strategy for the efficient and selective separation of phenol.