A highly robust and water permeable thin film composite membranes for pressure retarded osmosis generating 26 W·m−2 at 21 bar

Abstract

Herein, we fabricated two types of electrospun membrane using: 1) sulfonated poly (arylene ether sulfone), which needs chemical cross-linking to increase its mechanical strength, and 2) thermally rearranged poly (benzoxazole-co-imide), which is mechanically robust while requiring the hydrophilic coating. With a high porosity and low structure parameter of the support layer, two thin film composite (TFC) membranes were fabricated via interfacial polymerization on the support layer using 1,3,5-bezenetricarbonyl trichloride (TMC) and m-phenylene diamine (MPD) monomers. Chlorine modification using NaOCl solution was applied to two TFC membranes (denoted as XBPSH-TFC-Cl and XPBO-TFC-Cl, respectively) to improve water permeability (A) of the polyamide selective layer, while maintaining decent salt rejection values (R). As a result, the highly efficient XPBO-TFC-Cl achieved a peak power density of 26.6 W·m−2 at 21 bar using 1 M NaClaq and deionized (D.I.) water as draw and feed solutions, respectively. According to the modeling results, XPBO-TFC-Cl was less affected by the adverse phenomena (such as concentration polarization and reverse salt permeation), and showed lower performance reduction for various feed sources compared to XBPSH-TFC-Cl. These results demonstrate the potential of the next generation TFC membranes, which are commonly used for power generation and liquid separation.