Study On Improvement Of The Mass Transfer Of Leaching And Absorbing Geniposide Under Ultrasonic Field

Ultrasound is a kind of high frequency mechanical wave which can effectively improve mass transfer and heat transfer, change physical-chemistry phase equilibrium, fasten chemistry reaction rate.In this paper,the influence of ultrasound on the solid-liquid extraction and the adsorption phase equilibrium were investigated by using the effective component-geniposide of the mature gardenia fruit as the experimental object. In the extraction experiment,extraction isotherm of geniposide on the fruit, the extraction kinetics of the geniposide,the extraction kinetics of the geniposide by stirring and by pure are tested separately. In the adsorption experiment,the adsorption isotherm, bath adsorption dynamics and the breakthrough curves of the geniposide on 1300 resin and under different ultrasound intensity were tested.The result of the experiment indicated that the capability of adsorption decrease with ultrasound intensity, while the rate of the extraction and adsorptin increase.The model resulst also showed that the theoretical value of the homogeneous model considering intrapartical diffusion and outside-surface diffusion with Freundlich phase equilibrium equation are agfeeable with the experimental value. At the same time, the intrapartical diffusion and liquid internal mass transfer can been enhanced by ultrasound field, owing to additional stirring, the increasing rate of intraparticle diffusion coefficient is enhanced , while that of the liquid film mass transfer coefficient is reduced under ultrasound field. On the basis ofanalysing the mechanism of improvement of the adsorption mass transfer by ultrasound field, a batch model cosindering pore difusion and surface diffusion, and a fixed-bed homogeneous model of mass transfer is developed..