The characterization of GOMs, VGMs, VG-M and VG-S samples were carried out using a range of analytical techniques. The surface hydrophobicity was measured by contact angle using the contact angle goniometer from Ossila. The VC concentration of the feed and permeate solutions was quantitatively analyzed by ultraviolet-visible spectrophotometer (UV-vis, PerkinElmer Lambda 365) with an external standard curve method. Field-emission scanning electron microscopy (FE-SEM, FEI Nova NanoSEM 230) was applied to characterize the surface morphology and cross-sectional structure of the synthesized materials and fabricated membranes. In addition to SEM, the topological information of GO sheets, VG-M and VG-S was also provided by atomic force microscopy (AFM, Bruker Dimension ICON SPM). Transmission electron microscopy (TEM, JEOL JEM-F200 Multi-Purpose FEG-S/TEM) was used to study the dimension of GO and VG-M sheets on lacey carbon grids. The X-ray diffraction (XRD) patterns were obtained to investigate the interlayer spacing (d-spacing) of the materials and membranes using PANalytical Empyrean I Thin-Film XRD at 45 kV 40 mA, and PANalytical MPD at 40 kV 40 mA with Cu Kα radiation (λ = 0.154 nm). The Fourier transform infrared spectroscopy (FT-IR) was characterized in ambient temperature with PerkinElmer Spectrum 100 spectrometer. The samples were scanned using universal attenuated total reflectance (ATR) mode from wavenumber of 650 cm -1 to 4000 cm -1 for obtaining the functional group information. The chemical composition was also investigated by an X-ray photoelectron spectrometer (XPS, Thermo ESCALAB250i) using a monochromatic Al Kalpha soft X-ray source for surface analysis and a monoatomic argon ion beam for depth profiling. Raman spectra were recorded from 1000 cm -1 to 3500 cm -1 on a Renishaw inVia Raman Microscope with 532 nm excitation laser.