Forward osmosis (FO) is an emerging membrane-based technology which has the potential to reduce the costs and environmental impacts of desalination and water treatment. Although the understanding of RO principles and interest in its use precede current investigations by several decades, recent developments have greatly improved the prospects that this technology may be applied to productive commercial use. The most significant of these developments has been the identification and characterization of a set of solutes which may be used to create high osmotic pressures necessary for high rates of membrane water flux and high feedwater recoveries which may also be efficiently removed from the product water and recycled for process reuse. A second development of great importance has been the introduction of thin, highly selective semi-permeable membranes which enable high water flux in FO systems. A recurring challenge in the selection of a FO draw solute is in the requirement that it be, as completely as possible, removable from and recyclable within the FO system. A second criterion is that it should create a high osmotic pressure, particularly if it is intended to be used in desalination of the concentration of high osmotic pressure feed streams. Thirdly, it is important that the solute be well rejected by the semi-permeable membrane employed. These have proven a difficult set of requirements to meet, but a potential breakthrough has recently been achieved in research at Yale University, in the identification of a set of draw solutes which appear to meet these criteria.
This presentation is available to AMTA Members only.
- Robert McGinnis
- Yale University
- AMTA Biennial Conference, Las Vegas, NV
- Biennial Conference
- Forward osmosis (FO), solutes, flux, asymmetric semi-permeable membrane, Dr. Sydney Loeb, draw solutes, reactive gases, precipitable salts, volatile alcohols, salts with thermally dependent solubilities, non-removable solutes, Yale University