Draw solute selection

In spite of the great potential of the saline gradient membrane processes, FO and PRO are still regarded as immature technologies since some remaining limitations have hampered their real-world implementation. One of the key challenges to the future advancement of these processes is identifying a suitable draw solute. Hence, in this chapter, the research history of draw solute development is comprehensively reviewed based on material classification, recovery method, and application filed, to identify the ideal conditions for selecting an optimized draw solute in specific applications. This chapter will hopefully serve as a useful and practical guide for the selection and development of draw solutes to interested parties.