Permeability of nanobubbles-graphene oxide membrane and its dye retention performance

Graphene oxide (GO) membranes were widely used for dyestuffs separation in complex wastewater due to their excellent physical and chemical properties and unique water channeling. The formation of nanobubbles-graphene oxide (NBs-GO) membranes by adsorption of nanobubbles (NBs) onto GO was expected to improve the dye separation performance of the membranes. The NBs-GO membranes were used to treat dyestuffs wastewater simulated by methylene blue solution. The water permeability, retention rate and stability of the membranes were determined, and the effects of factors such as dyestuff type and concentration, membrane thickness, and GO preparation conditions on the membrane performance were investigated. The results showed that the water permeability of the NBs-GO membrane was 50.8% higher than that of the traditional GO membrane, and the retention rate of methylene blue was maintained at 99.88%, which was superior to that of the traditional GO membrane. In addition, the NBs-GO membrane showed good stability within 72 h, and the retention rate was always maintained above 90%. The NBs-GO membranes maintained excellent water permeation performance even when the dyestuffs type, concentration and membrane thickness were changed. Therefore, the introduction of nanobubbles provides a new idea to improve the dyestuffs separation efficiency of GO membranes, which shows great potential in the treatment of dyestuffs wastewater, and this discovery is expected to open up a new path for the advancement of dye wastewater treatment technology.