Ultrathin Graphene Oxide-Based Nanocomposite Membranes for Water Purification

Two-dimensional graphene oxide (GO)-based lamellar membranes have been widely developed for desalination, water purification, gas separation, and pervaporation. However, membranes with a well-organized multilayer structure and controlled pore size remain a challenge. Herein, an easy and efficient method is used to fabricate MoO₂@GO and WO₃@GO nanocomposite membranes with controlled structure and interlayer spacing. Such membranes show good separation for salt and heavy metal ions due to the intensive stacking interaction and electrostatic attraction. The as-prepared composite membranes showed high rejection rates (˃70%) toward small metal ions such as sodium (Na⁺) and magnesium (Mg²⁺) ions. In addition, both membranes also showed high rejection rates ˃99% for nickel (Ni²⁺) and lead (Pb²⁺) ions with good water permeability of 275 ± 10 L m^-2 h^-1 bar^-1. We believe that our fabricated membranes will have a bright future in next generation desalination and water purification membranes.