Petroleum Refinery Waste-Derived Graphene Oxide for Sustainable Membranes in Wastewater Treatment

Abstract Petroleum coke, a carbon-rich waste generated in large quantities from refinery thermal cracking units, presents major disposal and environmental challenges. This study introduces a sustainable strategy to convert petroleum waste coke into high-value graphene oxide (GO) nanosheets using a thermochemical oxidation and exfoliation method modified from the Hummers method. The synthesized GO was subsequently functionalized with triethylenetetramine (TETA) to produce GO-TETA nanocomposites, which were incorporated into polyamide (PA)-modified polyvinylidene fluoride (PVDF) membranes for advanced industrial wastewater purification. The materials were extensively characterized using multiple characterization techniques to confirm successful oxidation, amine grafting, and membrane integration. The GO-TETA-based PVDF membranes exhibited excellent performance, achieving over 97% removal of organic hydrocarbons, over 93% removal of heavy metals (Pb2+, Cu2+, Cr3+, Cd2+), and over 90% salt rejection, while maintaining a stable water flux of 42 L m−2 h−1 at 20 bar over 8 h of continuous operation without structural degradation or severe fouling. These results demonstrate simultaneous broad-spectrum contaminant removal within a single membrane platform, exceeding most reported GO-based systems. Overall, this work demonstrated an effective waste-to-resource pathway that transforms petroleum coke into functional GO nanosheets and the corresponding membrane materials, offering an economically viable and environmentally sustainable solution for industrial wastewater treatment.