Progress, Challenges, and Prospects of Forward Osmosis (FO) and Pressure Retarded Osmosis (PRO) as An Alternative solution for Water and Energy Crisis

Abstract

Blue energy is found fascinating to be implemented in Indonesia, the largest archipelago country of which 70% territory is covered with water. The utilization of osmotic-driven membranes in addressing water and energy scarcity has received much attention. Forward osmosis (FO) and pressure-retarded osmosis (PRO) are two osmotic driven membrane processes that utilize draw solution with higher osmotic pressure than the feed solution to drive the water flux. These processes are less energy-intensive compared to other pressure-driven membranes. However, the applications of each of these processes are still limited due to three main challenges, which are the production of high-performance membrane materials for high water flux and selectivity, the selection of draw solutions, and the need for post-treatment to recover the draw solution. In this study, recent developments in FO and PRO membrane processes are reviewed, then the potentials of the utilization of osmotic-driven membrane in addressing the water and energy crisis are discussed and evaluated. The review is based on asymmetric polyamide (PA) membranes with strong porous support performing in FO and PRO processes. Draw solution plays a significant role in attaining good performance in osmotic-driven membrane processes. Integrated FO/PRO/RO hybrid processes have been proposed and evaluated in terms of their energy consumption and carbon footprint. The results indicate positive prospects of these hybrid processes pushing forward the research on continuous and self-sustaining osmotic-driven water and energy productions.