Selective adsorption of triterpene acids on cerium oxide nanoparticles

Researches on the adsorption for triterpene acids by cerium oxide nanoparticles (CeO₂ NPs) as adsorbent were carried out. The results demonstrated that CeO₂ NPs could selectively adsorb triterpene acids. Using triterpene acid standards as model compounds, the adsorption and desorption conditions were optimized. The adsorption was conformed to be a pseudo-first-order model and single-layer adsorption after being characterized by adsorption kinetics and adsorption thermodynamics. It has been found that the adsorption efficiency of open-ring type triterpene acids was better than that of closed-ring type triterpene acids. The CeO₂ NPs was successfully applied to enrichment and selective separation of triterpene acids in the crude extract of Poria cocos. The adsorption by CeO₂ NPs has the advantages of high efficiency, low energy consumption and high selectivity, and is expected to become an alternative to traditional triterpene acid separation techniques such as chromatographic separation methods and liquid-liquid extraction enrichment techniques.