High-performance and durable pressure retarded osmosis membranes fabricated using hydrophilized polyethylene separators

Abstract

A high-performance and durable thin-film composite (TFC) pressure retarded osmosis (PRO) membrane was fabricated using a polyvinyl alcohol (PVA)-coated polyethylene (PAPE) support via toluene-assisted interfacial polymerization (TIP). The PVA coating uniformly hydrophilized the extremely thin (similar to 8 mu m) polyethylene (PE) support with a highly porous structure while marginally deforming the support structure, resulting in a very low structural parameter (similar to 235 mu m). The TIP process produced a polyamide selective layer with remarkably higher water permeability (similar to 8.78 L m(-2) h(-1) bar(-1)) than those of commercial HTI membranes (0.56-1.40 L m(-2) h(-1) bar(-1)). Furthermore, despite its extreme thinness, the PAPE-supported TFC (PAPE-TFC) membrane had higher mechanical properties than the commercial membranes owing to the superior mechanical strength of its PE support. Hence, the PAPE-TFC membrane achieved an unprecedentedly high power density of similar to 35.7 W m(-2) at an applied pressure of 20 bar using a deionized water feed solution and a 1.0 M NaCl draw solution, which significantly outperformed commercial and any other reported lab-made PRO membranes. The mechanically robust PAPE-TFC membrane also enabled stable long-term PRO operation under high pressure conditions.