ABSTRACT
Although the feasibility of harvesting osmotic power via pressure-retarded osmosis (PRO) process was recognized in the early 70s, further advancement of the PRO technology had been hindered by the lack of effective membranes. A significant progress in the development of PRO membranes has been achieved during the last decade. Moreover, novel flat-sheet polymeric membranes with desired structure, mechanical robustness, and permeation characteristics have been successfully developed for PRO applications. This chapter summarizes what has been accomplished regarding the flat-sheet polymeric membranes and provides insights for the development of next-generation PRO membranes. After a brief introduction on the performance of the existing reverse osmosis/nano-filtration and forward osmosis membranes in the PRO process, this chapter mainly focuses on novel and state-of-the-art flat-sheet PRO membranes. Furthermore, the requirements for fabricating effective PRO membranes are discussed and future perspectives are presented.
