Ths paper focuses on me mechanism of interfacial mass transfer of a single bubble. based on chemi cal potential driving force, an approach for calculating interracial concentration in practical process is proposed. The absorption proc esses of bubble under bom quiescent an d mobile conditions ale analyzed and discussed respectively. For a staftonary absorption. only in me case of liquid bulk concentration near saturated value. Me tefacial concentration could close to me equilibrium value：For a moving bubble, under ordinary operating condi. Tion (y0>1), me interfacial concentration is far from its equilibrium. Only under bulk concentration near saturated value or a smaller Yo (Yo<0.1) which may involve me complication of additional resistance at interface induced surface contamination or sufactant added. me interfacial concentration could be approximate to equilibrium value. The interfacial concentration close to me interface on liquid side for a single CO, bubble absorbed by methanol measured using a modern optical instrumentation in which me laser holographic interference memOd is adopted wim a real-time and amplification technique. Experimental results show mat me interfacial concentration decreases significan tly with increasing Re an d is far from the eq uilibrium one in a larger Re ran ge. Experiments validate proposed mode1.

Laser Doppler Anemometer has been used to measure the flow field characteristics near the interface around a moving bubble in the presence of ultrafine particles. In order to model a moving bubble the bubble was fixed into the counter-flow liquid by a metal mesh. Experimental materials are air and water and the parti-ties are complex oxidate powder. Experiments were carried out under the operating conditions: the liquid flow velocity Uo is 12.6cm/s, the equivalent diameter d, is 0.6cm, the mass concentration of particle is 0.2%, the average particle diameter is about 10mm and the density is 2g/cm3. The velocity profiles of both frontal and tail-vortex areas were measured respectively. The experimental results show tllat the velocity fields RIFe obviously changed in the existence of particles. In the frontal area of the bubble both tangential and normal velocities de-crease due to the presence of particles, but in tail vortex area, the tan gential velocities increase remarkably and normal velocities rise gradually from the center towards the fringe in the opposite tendency to that of no par-ficles. The influences of flow field change in the presence of particles on gas-liquid mass tran sfer are analyzed and discussed.

Mass transfer in gas-liquid bubbling processas is commonly encountered in chemical engineering practice. Forthe research on interphase ma transfer. It is very importantto begin with the description of the interface it self, in which the concentration near the interface has to be pri-marily measured. Formerly, most models developed for describing interphase interphase mass transfer were pragmatically simplified in both of the interface an hydrodynamics. An apparent difficulty is to measure the concentration distribution in the intefacial region. This subject lay dormant until the development of holographic interference technique in early seventies and the experim ental study initiated by VII and his students in nineties [1, 2]. In this paper, two holographic intefer-ometers are successfully used to study the concentration field near the gas-liquid interface of a riaing bubble. The present study may be helpful to broaden the knowledge about the mechanism of mass transfer in bubbling process.

The influence of the third component on gas-liquid mass transfer was studied by use of laser holographic interferometry. Four surfactants were added respectively and experimental results show that the microamount of surfactants can change obviously the concentration near the interface on bubble mass transfer process, which indicated that the third component has a significant effect on the bubble mass transfer process.

Based on the method of molecular therm odynamics, them asstransfer mechanism at gas-liquid interface is studied theoretically, and a new mathematical model is proposed. Using laser holographic interference technique, the hydrodynam ics and mass transfer characteristics of CO2 absorption are meas ured. It is shown that the calculated results are in good agrement with the experimental data.