A molecular imprinting polymer based on computer-aided design: Selective enrichment and purification of synephrine from the extract waste liquid of Citrus aurantium L

A molecularly imprinted polymer (MIPs) was prepared based on a computer-aided design, which was used to selectively enrich and purify synephrine (SYN) from the extract waste liquid of Citrus aurantium L. The suitable functional monomers, cross-linkers and reaction systems for preparing MIPs were quickly screened with density functional theory (DFT) calculation to effectively avoid the design blindness of molecularly imprinted material. The synephrine molecularly imprinted polymer (SYN-MIPs) with imprinted holes and magnetic properties were prepared with nano Fe3O4 as the core, and the structure, morphology, magnetic property and adsorption behavior were studied and the interaction mechanism of the adsorption process was clarified by DFT calculations. The saturated adsorption of SYN-MIPs for SYN was as high as 47.38–53.68 mg/g within 298 K to 308 K. The adsorption behavior of SYN-MIPs for SYN was well fit for the Freundlich adsorption and the pseudo-second-order kinetic model. It was worth mentioning that SYN-MIPs showed distinguished re-usability and specific recognition. The imprinting factor and selection factor to SYN were 3.13 and 2.43, respectively. The selective enrichment and purification of SYN from the extract waste liquid of Citrus aurantium L. achieved satisfactirily, and the purity of SYN enriched to 93.73% while the concentration of SYN was only 1.73% in the extract waste liquid. The study provides not only an efficient adsorption separation polymer materials but also a practical for the enrichment and purification process of SYN from the extract waste liquid of citrus plants.