Osmotic distillation mass transfer

In these systems, the interface between two phases is located at the high-throughput membrane porous matrix level. Physicochemical, structural and geometrical properties of porous meso- and microporous membranes are exploited to facilitate mass transfer between two contacting immiscible phases, e.g., gas-liquid, vapor-liquid, liquid-liquid, liquid-supercritical fluid, etc., without dispersing one phase in the other (except for membrane emulsification, where two phases are contacted and then dispersed drop by drop one into another under precise controlled conditions). Separation depends primarily on phase equilibrium. Membrane-based absorbers and strippers, extractors and back extractors, supported gas membrane-based processes and osmotic distillation are examples of such processes that have already been in some cases commercialized. Membrane distillation, membrane... 

Diffusion is the main mechanism involved in the mass transfer during osmotic distillation and the resistance to mass transfer comes from both membrane stmcture and presence of air trapped within the membrane pores. While the former resistance can be described by Knudsen diffusion Equation 19.26, the latter is described by molecular diffusion Equation 19.27. 

Celere, M. and Gostoli, C. The heat and mass transfer phenomena in osmotic membrane distillation. Desalination, 147, 133, 2002. 

Sheng, J., Johnson, R.A., and Lefebvre, M.S. Mass and heat transfer mechanisms in the osmotic distillation process. Desalination, 80, 113, 1991. 

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