A gas-liquid mass transfer apparatus and a Schlieren system were built to visualize the Marangoni convection patterns generated in the process of CO2 desorption from ethanol in a direction perpendicular to the interface. During the desorption

uniformly-distributed and gyrate convection patterns were observed

which tend to merge and develop with time. In addition

the information such as concentration distribution and interfacial tension gradient in the mass transfer process was studied through quantitative schlieren method. The results indicate that larger interfacial tension gradient locates at the edge and center of convectional cell

drives the movement of interfacial fluid and couples with the buoyancy effect

forming the circulating flow near interface. This circulating flow leads to a concentration distribution that has higher value at the edge and lower value inside the convectional cell. This accelerates the renewal rate of interfacial fluid element so that the mass transfer is enhanced.