Recent development of pressure retarded osmosis (PRO) hollow fiber membranes

The unique advantages of higher surface area per module and self-support configuration for hollow fiber membranes make this type of membranes potentially suitable for pressure retarded osmosis (PRO) processes. In the last decade, a significant progress in rational design and fabrication of effective hollow fiber PRO membranes has been achieved. Both integrally formed phase inversion hollow fiber membranes and thin-film composite hollow fiber membranes with proper membrane structures, balanced permeation properties, and good mechanical strength have been developed. This chapter provides a big-picture overview of the current state of hollow fiber PRO membranes, showcasing the best-performing materials and fiber structures as well as examining trends toward addressing challenges in fiber mechanical strength and water flux to provide guidelines on pathways toward improving membrane performance. In the last, we discuss the future research directions and perspectives of hollow fiber membranes for PRO osmotic power generation.