Room-Temperature Synthesis of Anionic Covalent Organic Framework Monolithic Materials for Efficient Capturing of Berberine Hydrochloride.

An anionic covalent organic framework (COF) was constructed using 2,5-diaminobenzenesulfonic acid as an ionic building unit. The incorporation of sulfonate functionalities endows the framework with permanent anionic sites, thereby enabling selective ion-exchange interactions with cationic species. The adsorption performance toward berberine hydrochloride (BBH) was systematically investigated by optimizing pH, ionic strength, adsorbent dosage, extraction time, and elution conditions. Rapid adsorption equilibrium was achieved within 10 min, and the kinetic data were well described by a pseudo-second-order model, indicating a chemisorption-dominated process. Under optimal conditions (pH 11, 303 K), the maximum adsorption capacity reached 1082.4 mg g-1. The material maintained high adsorption efficiency in the presence of competing cations, demonstrating pronounced selectivity arising from electrostatic interactions. Moreover, it retained over 90% of its initial adsorption capacity after five adsorption-desorption cycles, confirming its structural stability and recyclability. These results highlight the effectiveness of introducing ionic functionalities into COF architectures to achieve high-capacity and selective adsorption of alkaloid compounds, providing a viable platform for the separation and analysis of BBH in complex herbal matrices. The design and synthesis of novel COF porous adsorption materials will play a crucial role in the separation and analysis of natural products.