Abstract: In this work, deep eutectic solvent-based magnetic molecularly imprinted polymer nanoparticles (DES-MMIPs NPs) for adsorbing naringin (NG) from lime peel were successfully developed employing carboxyl-functionalized Fe3O4 nanoparticles (Fe3O4@COOH NPs) as the magnetic carrier, a deep eutectic solvent (DES) as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The DES-MMIPs NPs were characterized for their morphology, thermal stability, crystal structure, and magnetization. Their adsorption performance was assessed through static and dynamic adsorption experiments, specificity, reusability and stability tests, and Scatchard and first-order/second-order kinetic simulation analysis. This study investigated the effects of different adsorption conditions on the adsorption efficiency of the DES-MMIPs NPs. Finally, the DES-MMIPs NPs were applied to extract NG from lime peel. The synthesized DES-MMIPs NPs had an average particle size of (9.16 ± 1.68) nm and exhibited excellent crystal structure, magnetic properties, and thermal stability. Under optimal conditions, the adsorption capacity of the DES-MMIPs NPs reached up to 35.82 mg/g. The adsorption mechanism encompassed both specific and non-specific interactions, and the adsorption process was better described by the pseudo-second-order kinetic model. The imprinting factor of the DES-MMIPs NPs was determined to be 1.96, and the selectivity factors for the structural analogs luteolin, acacetin, and epigallocatechin gallate were 1.73, 1.32, and 3.38, respectively, demonstrating its good selectivity. After five adsorption-desorption cycles and 120 d of storage, the DES-MMIPs NPs still had a relatively high adsorption efficiency. Furthermore, the yield of NG extracted from lime peel by the DES-MMIPs NPs was 31.42 mg/g, validating their efficacy for practical applications.

Key words: naringin; extraction; deep eutectic solvent; magnetic molecular imprinted polymers