The Variations of Structure and Water Flux Performance of Porous Alumina Supported Graphene Oxide Membrane During Heat Treatment Process

Abstract

Graphene oxide membrane was fabricated based on a silane-modified Al2O3 ceramic substrate via a parallel dip-coating method. The effect of thermal treatment on the structure and performance of graphene oxide membranes was mainly studied in this paper. The thermal behaviours of graphene oxide powder and membranes were analysed by thermogravimetry (TG) and differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were applied for micro-morphology analysis. The category and content of chemical bonds were studied by fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS), and the interplanar spacing was investigated by X-ray diffraction (XRD). It was found that the thermal treatment temperature should not exceed 350 °C in order to ensure the integrity of the graphene oxide basic structure. The content of functional groups in graphene oxide was altered along with various temperatures, which led to changes in the contact angle and hydrophilicity. The pure water flux reached 15 L m–2 h –1 under 0.2 MPa pressure when the ceramic substrate was coated with 0.5 mg/mL graphene oxide dispersion and treated at 190 °C. The study indicates that the performance of the graphene oxide/ceramic composite membranes can be optimized by heat treatment.