Comprehensive simulation to uncover the ideal properties of a hollow fiber forward osmosis membrane module for the seawater desalination process

Abstract

Desalination with forward osmosis (FO) membranes is an attractive method, achieving an efficiency superior to that of reverse osmosis (RO), which has been improved for many decades, is difficult. Although many FO membranes have been developed, there are no guidelines in membrane development to make FO highly efficient. This paper quantitatively investigates whether FO desalination can be potentially superior to RO desalination, and, where so, we uncover the range of required membrane properties. The results show that it is difficult for the FO method with current hollow fiber modules to exhibit process performance superior to that of the present RO method with spiral-type membranes. However, if the water permeability of such membranes can be increased threefold, then the energy consumption of FO desalination can be reduced to 70 % of that of RO desalination. Thus, this study proposes guidelines regarding membrane properties, such as support layer thickness, water permeability, and rejection performance, which will be required when FO membranes are further advanced in the future.