On the importance of selectivity and support layer compaction in pressure retarded osmosis

Abstract

Abstract In this work, we use a modified thin film composite RO membrane to examine the impacts of selectivity and compaction on the performance of pressure retarded osmosis. RO membranes are promising platforms to study PRO because they are tolerant to typical PRO pressures and are well characterized for permeance and selectivity. Their availability across a range of selectivity (from nanofiltration to seawater RO) also allows us to systematically investigate the impact of selectivity on PRO power density under real PRO conditions. Parallel modeling efforts found that experimentally measured power densities for these membranes were less than 50% of predicted ideal values due to compaction. Interestingly, the highest selectivity membranes, which corresponded to the least permeable, exhibited the highest power densities.