Forward osmosis applications

For the forward osmosis applications in both desalination and wastewater treatment, the process of forward osmosis acts as a pretreatment process, due to which the membrane fouling problem can be significantly reduced. 

Figure 16.13 Example of a continuous forward osmosis application with recovery and recycle of the draw solution.

Another useful application of FO is the so-called osmotic backwash for cleaning RO membranes [62]. TFC membranes cannot be backwashed because the top thin layer can get detached. However, since forward osmosis transfers pure or fresh water through an RO/NF membrane under osmotic pressure, it can be used to backwash and clean the membrane with the permeate without the risk of damaging the membrane. One process operation is described below ... 

Application of Forward Osmosis to Reduce Produced Water Injection Volumes... 

Osmosis and Its Applications, Fig. 1 Forward osmosis profiles of the solution concentration and the osmotic pressure under the effects of membrane stmetures and orientations, (a) A symmetric dense semipermeable membrane with only ECP effects, i.e., concentrative ECP and dilutive ECP. (b) An asymmetric membrane with the dense-selective layer (DSL) facing against draw solution (normal mode) with the profile of the solution concentration illustrating concentrative ICP and dilutive ECP. (c) An asymmetric membrane with the porous support layer (PSL) facing against draw solution (reverse mode) with the profile of the solution concentration illustrating dilutive ICP and concentrative ECP. The key parameters Ch... 

Osmosis and Its Applications, Fig. 2 Schematic illustrations of 2-D simulation domains of reverse osmosis, forward osmosis, and pressure-retarded osmosis. The... 

Osmosis and Its Applications, Fig. 4 Schematic of power generation principle for a forward osmosis power plant [9]... 

The term draw solution denotes the concentrated solution of forward osmosis or the dilute solution of reverse osmosis. Further studies of draw solutions should mainly focus on the field of forward osmosis due to its important role in separating processes as abovementioned applications in the previous section. Effective draw solutions showing high osmotic pressure, good regeneration property, and less fouling properties are needed. 

Cath, T.Y, Childress, A.E. Elimelech, M. (2006) Forward osmosis principles, applications, and recent developments. Journal of Membrane Science, 281 (1-2), 70-87. 

Cath, Tzahi Y., Amy E. Childress, cuid Menachem Ehmelech, Forward Osmosis Principles, Applications, and Recent Developments, Journal of Membrane Science, 281,2006 (pages 70-87). 

Additional present and potential applications involving polymeric membranes include controlled release of drugs for medical applications, electrical power generation from forward osmosis and reverse elearodialysis, biomedical applications including hemodialysis and diagnostic applications, bioanalysis, sensors, and electrochromic displays. ... 

In liquid separation, hollow fiber membranes based on PBI have shown excellent performance for pervaporation dehydration of organic liquids. For example, a dual layer PEI-PBI hollow fiber membrane with an outer selective layer of PBI showed better performance than most other polymeric membranes in pervaporation dehydration of ethylene glycol. Sulfonation modifications of PBI membranes have demonstrated excellent separation efficacies in the dehydration of acetic acid. Studies have shown that PBI hollow fiber membranes were effective in separating chromates from solutions. Also, PBI nanofiltration hollow fiber membranes are promising candidates as forward osmosis membranes. In gas separation, recent studies sponsored by the Department of Energy at Los Alamos National Laboratories and SRI International demonstrated potential applications of PBI membranes in carbon capture and Hj purification from synthesis gas streams at elevated temperatures. H2/CO2 selectivity > 40 has been achieved at H2 permeability of 200 GPU at 250°C. ... 

Hoover, L.A., Phillip, W.A., Tiraferri, A., Yip, N.Y. Elimelech, M. (2011) Forward with osmosis emerging applications for greater sustainability. Environmental Science Technology, 45 (23), 9824-9830. 

Hoover LA, Schiffman JD, Ehmelech M. Nanofibers in thin-film composite membrane support layers enabling expanded application of forward and pressure retarded osmosis. Desalination 2013 308 73-81. 

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