Hydrodynamics in an expanded bed of large size ion‐exchange resin, and natural product adsorption

Successful applications of expanded bed adsorption (EBA) technology have been widely reported in the literature for protein purification. Little has been reported on the recovery of natural products and active components of Chinese herbal preparations using EBA technology. In this study, the hydrodynamic behavior in an expanded bed of cation resin, 001 × 7 Styrene‐DVB, was investigated. Ephedrine hydrochloride (EH) was used as a model natural product to test the dynamic binding capacity (DBC) in the expanded bed. EBA of EH directly from a feedstock containing powdered herbs has also been investigated. These particles are different from commercially available expanded bed adsorbents by virtue of their large size (205 to 1030 µm). When the adsorbent bed is expanded to approximately 1.3 to 1.5 times its settled bed height, the axial liquid‐phase dispersion coefficient was found to be of the order 10 −5 m 2 s −1 , which falls into the range 1.0 × 10 −6 to 1.0 × 10 −5 m 2 s −1 observed previously in protein purification. Because of the favorable column efficiency (low axial dispersion coefficient), the recovery yield and purification factor values of EH directly from a feedstock reached 86.5% and 18, respectively. The results suggest that EBA technology holds promise for the recovery of natural products and active components of Chinese herbal preparations. Copyright © 2007 Society of Chemical Industry