Pressure Retarded Osmosis as a New Way for Sustainable Power Generation from Salinity Gradients

Abstract

In this work, we combined a novel approach of O2 plasma and polydopamine (PDA) coating to improve the properties of a model RO membrane. The O2 plasma “opens up” the selective layer of the commercial polyamide RO membranes and significantly improves the water permeability. The O2 plasma modified membranes, which become more reactive and are therefore easier to coat, were then coated with PDA – a truly hydrophilic material. As far as of our knowledge this is the first time where O2 plasma is used for the PRO application. All the modified membranes exhibited high water permeability and the PDA coated RO membrane exhibited the best performance in terms of salt rejection. Moreover, PDA coating was applied on the porous support layer of the membranes as well and it successfully enhanced the hydrophilicity of the membrane. As far as we are aware, this is also the first time when the support side of the membrane for PRO was modified for such purpose. The membrane modifications offered great opportunities to improve the anti-fouling properties of the RO membrane and opened up a new possibility for the development of PRO membranes.

Keywords: Pressure retarded osmosis, O2 plasma, membrane modification, polydopamine