关键词: L-缬氨酸, 离子交换, 分离, 动力学, 穿透特征

Abstract: The separation effects of different types of resins, the mass transfer kinetics and the rate-controlling step, the breakthrough behavior in a fixed bed were studied respectively in order to investigate the kinetics and the dynamic breakthrough characteristics for the L-valine separated by ion exchange. The results showed that the adsorption capacity of strong acidic cation exchanger resin, with a better separation effect, were five to eight times that of other resins, meanwhile their selectivity was from 1.3 to 1.8. L-valine with amphoteric ionic sates in a neutral (or slightly acidic) solution, was beneficial to its exchange adsorption. Moreover, the pseudo-second order kinetic model was found to describe adsorption process of the L-valine well with 001×7 resin as a separation media, such a process was affected by the particle and the liquid film diffusions together at early stage and then by multiple factors at medium-latter stage. Thomas and Yoon-Nelson models could describe breakthrough behaviors of the L-valine and the L-leucine well. The equilibrium adsorption capacity qe, volume adsorption capacity N0 and operation time τ decreased gradually with enhancing flow rate of the L-valine feed, whereas the equilibrium adsorption capacity qe and volume adsorption capacity N0 increased but operation time τ decreased gradually with increasing feed concentration of the L-valine. The ratio of height to diameter should be less than 5 and had an opposite trend to the effect of feed concentration change of the L-valine.

Key words: L-valine, ion exchange, separation efficiency, dynamics, breakthrough characteristic