Study On Macroporous Resin Expanded Bed Adsorption Of Ginkgo Flavoid

Researching and developing the advanced techniques of traditional Chinese medicine (TCM) and natural drug contain extracting, condensing, separating, purification techniques and so on, with the goal of making the process continuous and reducing the dosage, which are of importance to TCM modernization. Adsorption and separation with macro-porous was usually operated in fixed bed mode. Despite its operation mode was simple, but it needed to be filtered before liquor perfuse into fixed bed. Otherwise, adsorbent was likely to be polluted and the fixed bed would be blocked up. Expanded bed adsorption (EBA) is widely researched in biochemistry separation. To a large extent, it shows that the expanded can be used to separate TCM and nature drug. In order to make the expanded bed adsorption to become an important technique, the basic characteristic of expanded bed adsorption must be understood clearly, such as expansion character, mixture performance, separation efficiency, and so on.Five kinds of macroporous resin, AB-8, ADS-17, ADS-5, ADS-F8, D2080, were used to study adsorption and desorption performance for ginkgo flavonoids. Spectrophotometry was used to determine the ginkgo flavonoids concentration. The results showed that AB-8 resin was best adsorbents to adsorb ginkgo flavonoids. The adsorption capacity of AB-8 macroporous resin was 46 mg/ml. Distribution of particle size (0.3mm～1.2mm) was suitable to expanded bed adsorption.Secondly,a set of expanded bed, with the diameter 50 mm and height 1000 mm, was built to adsorb the gingko flavonoid by macro-porous resins with peristalsis pump supplying liquid. The expansion character of AB-8 resin in expanded bed was studied. The relationship between superficial and average voidage was also investigated. Axial voidage was measured with improved micro-conductivity probe technique. A 20% v/v acetone solution tracer, with impulse sampling system, was used to investigate liquid mixed characteristics of expanded bed. At last, using AB-8 resin adsorbents, expanded bed adsorption performance was studied in different operation conditions. The results were showed below. The expansion character of AB-8 resin in a 50mm column was found to obey the Richardson-Zaki equation. At a stated expand ratio, the axial voidage of the bed increased with the increase of bed height, existed inhomogeneous distribution. At a fixed bed height, the liquid axial dispersion coefficient increased with the increase of liquid superficial velocity. Liquid axial dispersion coefficient was between 5×10^-6～4.5×10^-5m²/s. When the fixed bed was 20cm in height, the feed concentration is 0.525 mg/ml, and the velocity was 154 cm/h, the adsorption efficiency was maximum, which was 81.5%.