Two magnetic adsorbents β-CDPU@Fe3O4 and β-CDPU@(SiO2/Fe3O4) were synthesized by encapsulating Fe3O4 and SiO2/Fe3O4 composite magnetic beads by β-cyclodextrin polyurethane polymer (β-CDPU)

and adsorption and enrichment of polyphenolic natural product corilagin from Phyllanthus niruri L. herb plants by magnetic separation were studied. Both adsorbents were characterized by FTIR

XRD

SEM and TG/DTA techniques. The appearance of several new peaks in FTIR spectra around 1695

1617

1559

1259 and 1033 cm-1 was attributed to urethane and β-CD moiety. The adsorbent polymeric surface was rough with many protuberant lumps

folds and pores as observed by SEM. Both adsorbents were thermostable below 200℃

indicating suitability for separation usage at room temperature. Polymer content of the two adsorbents reached as high as 41.5% and 36.5%

respectively

based on the mass loss at high temperature in TG/DTA analysis. XRD showed that the crystal structure of Fe3O4 in both adsorbents was nearly the same as that of Fe3O4 and SiO2/Fe3O4 composite beads. Hence

β-CDPU encapsulation did not alter crystal structure of Fe3O4. Adsorption of corilagin by both adsorbents followed Langmuir adsorption isotherm

which was expected from double adsorption sites in β-CDPU skeleton. But the special interaction between Fe3O4 magnetic-core and corilagin

probably due to the complex formation of Fe(Ⅲ) and phenolic hydroxyl groups in corilagin molecule

made it difficult to elute corilagin and resulted in low elution and recovery yield of corilagin at 17.0% and 10.5%

respectively. SiO2 modification on Fe3O4 magnetic core was able to hinder such interaction and the adsorbent β-CDPU@(SiO2/Fe3O4) exhibited more favorable performance for corilagin enrichment with the elution yield of 41.0% and recovery yield of 22.8%. The corilagin enrichment from Phyllanthus niruri L. showed the adsorbent β-CDPU@(SiO2/Fe3O4) would find commercial application for recovery and enrichment of specific natural products from plant materials.