Liquid Membrane Process. a Survey of Multiple Emulsion Method. Applicability of the Reaction-Site Model

The multiple emulsion membrane process of separation, purification, etc. has been reviewed. The technique of membrane preparation, derivation and technical discussion of different mathematical formulae (asing Fick's first law of diffusion) in connection with the simple and carrier transport with or without chemical reactions, coupled co- and counter-transports and primary active transport have been described and related experimental studies referred to. The unsteady state behaviour of the emulsion droplets in regard to mass transport has been discussed. The hollow-sphcre, all holes filled-all holes empty, and reaction-site models suggested so far in view of harmonizing the experimental observations with the Fick's 2nd law have been mentioned. The recently proposed reaction-site model for high viscous emulsion droplets has been considered in some details. The potential applications of the liquid membrane multiple emulsion process in the technology of separation have also been discussed.