A multifunctional hierarchical porous SiO2/GO membrane for high efficiency oil/water separation and dye removal

Removing contaminants from wastewater is critical to secure the global water supply. Membrane technologies for water purification are exceptionally attractive due to their high efficiency and low energy consumption. The traditional porous polymer films, however, are easy to be fouled by the organic pollutants, causing pore blockage and deteriorated separation performance. We herein report the rational design of a porous SiO2/GO hybrid membrane by coupling graphene oxide (GO) nanosheets with SiO2 nanoparticles and using ethylenediamine to crosslink them, for efficient oil/water separation and dye removal. The SiO2 nanoparticles provide an excellent hydrophilicity and underwater superoleophobicity interface, resulting in efficient and antifouling oil/water separation with an outstanding rejection rate over 99.4% for different types of oil; and the hierarchical scaffold, formed from the hydrophilic GO nanosheets embedded with SiO2 nanoparticles, greatly facilitates the rapid permeation of water with a high flux rate of up to 2387 L m−2 h−1 for pure water and 470 L m−2 h−1 for oil/water separation. Moreover, the abundant functional groups on the GO surface also render this membrane with a high removal capability for dye blocking, enabling it to remove soluble pollutants in molecular dimensions as well. This design strategy not only provides an outstanding membrane for water purification but also sheds light on the design of multi-purpose functional membranes for a variety of energy and environment-related applications.