Dual-Layer hollow fiber membrane development for forward osmosis and osmosis power generation

Abstract

For the first time, polybenzimidazole (PBI)/ Polyacrylonitrile (PAN) dual-layer membranes with ultra-thin outer dense layer (about 1?m) and porous inner support layer were developed for forward osmosis (FO) and pressure retarded osmosis (PRO) applications.

In this work, polyvinylpyrrolidone (PVP) incorporation effects on the elimination of membrane delamination; polyhedral oligomeric silsesquioxane (POSS) incorporation effects on the membrane structure and permeability; ammonium persulfate (APS) post treatment effects on the membrane permeability were conducted and drew out some useful conclusions for membrane development. In addition, universal dual-layer co-casting method was developed for the research of the solution for elimination of membrane delamination; with this method, the time consumption for dual-layer delamination-free membrane development had been significantly reduced.

In summary, with its unique outer dense-selective skin, hydrophilic inner-layer and outer-layer structure, and easy processability, the newly developed PBI/PAN dual-layer membrane has shown promising results in both FO and PRO processes.