ON THE DIFFERENCE IN RATES OF ABSORPTION AND DESORPTION OF GASES

The critical times of bifurcation of the diffusion mode of unsteady ab sorption of sparingly soluble gases by a quiescent liquid layer as a f unction of various factors were theoretically and experimentally deter mined. Based on physical concepts of the mechanism of the interfacial transfer in the supercritical region, a relation was proposed for calc ulating the absorption rate to within a constant coefficient. A techni que was worked out for the experimental determination of the absorptio n rate as a function of the contact time, and experimental data were o btained on the absorption of argon and carbon dioxide from a carbon di oxide-nitrogen mixture by water and ethanol. The theory elaborated pro vided a unified description of the gas absorption rate in all studied systems and allowed us to find the critical time of transition from th e diffusion mode of gas dissolution in a quiescent liquid into the con vective mode governed by the capillary forces (the Marangoni effect). An explanation was offered for the experimentally observed substantial acceleration of the gas absorption rate in the supercritical region i n comparison with that in the diffusion mode.