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 prompting several studies. In this study, 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 using Fourier transform infrared (FT-IR), zeta potential, and X-ray photoelectron spectroscopy, X-ray diffraction measurements. Atomic force microscopy and water contact angle 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. Furthermore, 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 fouling process. Furthermore, the good stability of the semi-IPN was revealed via FT-IR after a 7-d continuous crossflow test. This work provides a guideline for physicochemical properties and microstructural design of novel RO membranes.