Free-Standing Graphene Oxide-Chitin Nanocrystal Composite Membrane for Dye Adsorption and Oil/Water Separation

Chitin nanocrystals modified by dopamine (D-ChNCs)/graphene oxide (GO) composite membranes were successfully prepared with the assistance of vacuum filtration. D-ChNCs/GO was analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize the surface morphology of the membrane. The hydrophilicity of membrane is dependent on the content of the hydrophilic D-ChNCs, which shows a sharp increase of pure water flux from 8.8 of pure GO to 135.6 L.m(-2).h(-1). The rejection ratio of methylene blue (MB) and Congo red (CR) is as high as 99.3 and 98.3%, respectively. In addition, the oil rejection ratio of the membrane is above 97.5%, exhibiting good oleophobicity. The recycle experiment also demonstrates acceptable recyclability and proper regeneration for practical application. In total, D-ChNCs/GO composite membranes with excellent hydrophilicity, good oleophobicity, and anti-dye and anti-oil fouling have great potential in wastewater treatment.