Hydrophilic pervaporation

While vapour permeation and hydrophilic pervaporation have readily found well-established areas for industrial application, in the case of organophilic pervaporation a clear industrial breakthrough has not yet been achieved. The reasons for this situation derive from the intrinsic character of this process and from the way some problems have been approached so far ... 

Another appUcation of membrane processes for MTBE removal studied in literature is the pervaporation, which represents an alternative to the stripping process discussed in chapter 3. Hydrophilic pervaporation is commonly used for the absolutation of alcohol which forms an azeotropic mixture at high ethanol content [128]. By the vaporization of the mixture through a thin membrane layer, the azeotrope is cleaved and water is evaporated leaving the pure ethanol in the retentate. 

Hydrophilicity Pervaporation Dehydration of water miscible organic solvents... 

Klamklang, S., Soontarapa, K. and Damronglerd, S. 2002. Preparation and characterization of hydrophilic pervaporation membranes from natural rubber latex based polymer. Sci. Asm 28 135-143. 

Pervaporation, as a non-integrated process, is typically utilized for dehydration and for the recovery or removal of organics from aqueous solutions and sometimes also for the separation of organic mixtures (Neel, 1995). Also many hybrid processes have been developed where PV is coupled with other processes, such as different membrane processes (e.g., reverse osmosis, or organophilic pervaporation coupled with hydrophilic pervaporation), distillation, reactive distillation and, of course, reaction. With these aspects in mind, PV appears particularly suitable to keep the concentration of a by-product low, or to continuously recover a product while it is formed. Note that these are the main objectives typically pursued in membrane reactors. 

Removal of water in PVRs PVRs with hydrophilic pervaporation membranes... 

Hydrophilic pervaporation membranes can be very selective, mainly because the materials for this type of membrane show both sorption selectivity and diffusion selectivity much larger than unity. So they are widely utilized in the dehydration of organic solvents, whenever water is the minor component. 

Although hydrophobic pervaporation membranes can be used to recover alcohol from fermentation broth, hydrophilic pervaporation membranes allow for the dehydration of water/alcohol mixmres (Figure 11.7). Hydrophilic pervaporation membranes can be applied to separate water from highly concentrated alcohol (>85%) (Abels et al., 2013). Two types of membranes have been explored in recent studies (1) zeoUte-based membranes and (2) polymeric composite membranes with polyvinylalcohol or polyimide as the active layer. 

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