[Preparation of Sulfonated Graphene Oxide Modified Composite Nanofiltration Membrane and Application in Salts...

In recent years, water resources are in short supply and seriously polluted. Increasingly more attention has been paid to the process of salt separation. The surface of the nanofiltration (NF) membrane is usually charged and can selectively allow the permeation of different ions. Based on the different charges on the NF membrane surface, in order to achieve a good separation of salt, the prepared graphene oxide with the sulfonic acid group was introduced into NF membrane material. Additionally, the SGO modified composite NF membrane was prepared by interfacial polymerization. Zeta potential analysis showed that the charge on the surface of the prepared NF membrane was more negative than that of the NF membrane without SGO. The peak of the ester group in the FT-IR analysis indicated that the sulfonate group was involved in the polymerization reaction. A Turing structure present on the surface of the membrane was evident through SEM pictures of the membrane surface. At a pressure of 0.2 MPa, the pure water flux can reach 45.85 L·(m²·h)^-1. The rejection of Na₂SO₄ was 98.23%, while that of NaCl was 24.93%. The 10 h operation can effectively separate SO₄^2- and Cl^-, which realized the salt recycling.