Membrane evaporation process

Recently, an in-depth review on molecular imprinted membranes has been published by Piletsky et al. [4]. Four preparation strategies for MIP membranes can be distinguished (i) in-situ polymerization by bulk crosslinking (ii) preparation by dry phase inversion with a casting/solvent evaporation process [45-51] (iii) preparation by wet phase inversion with a casting/immersion precipitation [52-54] and (iv) surface imprinting. 

Balaban, M., ed. (1991, May). Desalination and Water Re-Use Proceedings of the 12th International Symposium Economics Membrane Distillation Membrane Processes Evaporative Processes, Hemisphere, Bristol, PA. 

Membrane processes termed as osmotic distillation or membrane distillation could be shown to be applications of membrane contactor technology also. Both of these processes are based on gas membranes. Osmotic distillation, sometimes called osmotic evaporation, involves transfer of water vapor across a gas-fiUed membrane, the process is driven by a difference in water vapor pressure maintained across the membrane [58-59] by separate aqueous hquids. Membrane distillation is a process where water vapor transfer is driven solely by a temperature difference across the gas-fiUed membrane [60-61]. Water evaporates from a hot aqueous phase and condenses on a cooler surface. This process may be useful in desalinating water or producing pure water if a good natural source of warm water is available, such as in a geothermal process. 

The main advantages of the membrane distillation process over conventional distillation are the configuration of the evaporation surface can be made into various membrane modules with a compact area density, mist can be eliminated, and highly pure water can be obtained as product corrosion may be less than that with metal surfaces. 

Salient Features of Evaporation and Membrane Concentration Processes... 

Alves, V.D. and CoeUioso, I.M. Effect of membrane characteristics on mass and heat transfer in the osmotic evaporation process, J. Membr. Sci., 228, 159, 2004. 

Brodard, F., et al. New hydrophobic membranes for osmotic evaporation process, Sep. Purif. Technol, 32, 3, 2003. 

This method was one of the earliest used in making microporous membranes (5) and has subsequently been applied by Kesting for making reverse osmosis membranes in his dry or complete evaporation process (6). This process consists of a three-compound mixture a polymer, a volatile solvent and a third component, which by itself is a nonsolvent for the polymer. This... 

Figure 4.5 Schematic view of the membrane evaporation (ME) process.

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