Graphene Oxide Composite Membranes for Water Purification

Graphene oxide (GO) has attracted remarkable attention as a potential material in the fabrication of next-generation membranes with high water permeability and efficient purification. Herein, an easy and effective means of modifying GO lamellar with a phytic acid (PhA) molecule as both an inserter and a surface modifier was developed to fabricate high-performance GO-based membranes. As a result, the addition of PhA to the GO membrane enhanced hydrophilicity and enlarged the interlamellar spacing. The optimal GP-10 composite membrane displayed a high average pure water flux of 6.31 L m–2 h–1 bar–1 under an ultralow pressure nanofiltration condition, which was about 18.6 times higher than that of 0.34 L m–2 h–1 bar–1 for pure GO membrane. At the same time, it possessed the ability to reject different charged dye molecules with a rejection rate higher than 99.88%. In addition, the composite membrane also showed good structural stability under different pH conditions. This study not only provides a method to simply design GO-based membranes by introducing multifunctional small molecules but also sheds light on using such GO composite membranes in practical water separation applications.