Improving the permselectivity and antifouling performance of reverse osmosis membrane based on a semi-interpenetrating polymer network

Thin-film composite (TFC) reverse osmosis (RO) membranes whose ultrathin selective layer is composed of polyamide (PA) have been extensively employed in desalination and purification of water. However, the poor permeability, selectivity, and antifouling properties have limited their application, thus provoked several studies. In this work, a semi-interpenetrating polymer network (semi-IPN) based on PA and poly (N-vinyl-2-pyrrolidone) (PVP) was fabricated via in situ polymerization to enhance the permselectivity and antifouling property of RO membrane. The successfully fabricated PA/PVP semi-IPN was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, and Brunner-Emmet-Teller (BET) measurements. Atomic force microscopy measurement showed that the hydrophilicity of the membrane was substantially improved. The optimal resultant membrane (0.5-10s-NVP) showed 43.2% and 0.2% increments in water flux and salt rejection, respectively. The antifouling performance was substantially improved; the 0.5-10s-NVP exhibited a lower decline ratio in the normalized water flux after the Bovine serum albumin (BSA) fouling process. Furthermore, the good stability of the semi-IPN was revealed by XPS after a 7-d continuous crossflow test. This work provides a guideline for physicochemical properties and microstructural design of novel RO membranes.

Automated summary

In this study, a semi-interpenetrating polymer network (semi-IPN) based on PA and PVP was fabricated to enhance the permselectivity and antifouling property of thin-film composite reverse osmosis (RO) membranes. The optimized membrane showed significant improvements in water flux, salt rejection, and antifouling performance. XPS analysis confirmed the stability of the semi-IPN after continuous crossflow testing. This work provides a guideline for the design of novel RO membranes with improved physicochemical properties.