The effect of very high hydraulic pressure on the permeability and salt rejection of reverse osmosis membranes

Abstract

A stirred-cell reverse osmosis setup was used to demonstrate that a seawater reverse osmosis membrane can maintain excellent rejection at pressures as high as 172 bar. However, it was also demonstrated that there was a significant drop in permeability at high pressures - likely due to membrane compaction. A simple visco-elastic model was shown to be able to model the overall shape of the permeability curve in time. However, this model does not match the data well when pressure is removed and then reapplied. From the perspective of membrane performance, RO is feasible at high pressures but distinct challenges are presented by reduced permeability and increased variability in flux.