Pressure retarded osmosis – a multi-functional osmotic energy membrane-based harvest technology

Abstract

Pressure retarded osmosis (PRO) is a re-emerging membrane-based technology to harvest salinity gradient energy (SGE). Membrane is the key factor to further PRO development. Polymer blend is an effective method to enhance membrane properties. In this work, conventional polysulfone (PSf) and polyethersulfone (PES) were blended in 1:1 ratio to fabricate the support membrane. The intrinsic water and salt permeabilities of PSf:PES membrane were enhanced to 1.90 ± 0.42 LMH/bar and 0.46 ± 0.10 gMH, respectively compared to the pristine PSf and PES with only slight drop (1.2 %) in salt rejection of 97.7 %. PSf:PES membrane gave the highest water fluxes of 26.19 and 22.62 LMH at applied hydraulic pressure of 2 and 4 bar, respectively. The resultant power density obtained was 1.46 and 2.51 W/m 2 with the respective hydraulic pressure. The PSf:PES membrane substrate was found to bring a positive impact on the IP reaction with resultant fully cross-linked, leaf-like PA structure which ultimately gives a greater surface/volume ratio on its respective TFC PRO membrane performance.