Characterization of Osmotic Agent-added Salt Solution Properties for a Novel Pressure-retarded Osmosis System Utilizing Low-grade Energy

Abstract

We present a novel concept to obtain renewable energy by means of a pressure-retarded osmosis（PRO）system based on osmotic pressure enhancement by adding an osmotic agent（OA）to seawater. For the recycling of OA, low-grade heat energy is utilized. In this study, the osmotic pressure and thermoresponsive properties of the OA-added seawater were evaluated. Results revealed that the osmotic pressure of the 30 wt％ OA-added seawater dramatically increased to about 65 bar, and the OA solution had LCST of around 40 ℃, promising to separate by utilizing moderate heating.