This study investigates the sustainable synthesis of biobased graphene (BG) derived from coconut husk waste and its application in eco-friendly water-based drilling muds (WBM). The BG was prepared through thermal exfoliation of lignin and utilized as a fluid loss additive, while benzimidazole (BI) was incorporated to serve as a corrosion inhibitor. To optimize performance, the Taguchi method was combined with Grey Relational Analysis (GRA), targeting three key parameters: viscosity, fluid loss, and corrosion resistance. Structural characterization revealed that BG synthesized at 1000 °C exhibited improved graphitic ordering, with an average flake diameter of around 20 nm and an interlayer spacing (d-spacing) of 3.49 Å. In terms of performance, incorporating 0.5 wt% BG reduced fluid loss by 50%, while 5 wt% BI delivered an impressive corrosion inhibition efficiency of 96.9%. The optimal mud formulation was achieved using 0.5 wt% BG, 5 wt% BI, 60 min of mixing time, and 8 wt% bentonite. Altogether, this work highlights a sustainable pathway for drilling fluid formulation by valorizing agricultural waste and minimizing additive loadings—without compromising on performance or environmental compatibility.

Mechanical exfoliation of coconut husk into bio-based graphene for sustainable drilling mud: a Taguchi–GRA Study
    Abstract
    1 Introduction
    2 Materials and method
        2.1 Materials
        2.2 Preparation of BG
        2.3 Mud preparation
        2.4 Measuring viscosity of the mud formulation
        2.5 Measuring the fluid loss using API Filter Test
        2.6 Weight loss study
        2.7 Taguchi method’s design
    3 Results and discussion
        3.1 Bio-based graphene characterization
        3.2 Mud formulation rheology
        3.3 Corrosion inhibitors analysis
        3.4 Fluid loss analysis
    4 Optimisation
        4.1 Taguchi design
        4.2 Single response optimization
        4.3 Multi response optimization using grey relational analysis (GRA)
    5 Conclusion
    Acknowledgements 
    References

• Muhammad Taqi‑uddeen Safian(Materials Technology Research Group (MaTRec), School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Malaysia)
• Bothi Raja Pandian(Materials Technology Research Group (MaTRec), School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Malaysia)
• Mohamad Nasir Mohamad Ibrahim(Materials Technology Research Group (MaTRec), School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Malaysia) Corresponding author
• Nur Ezzah Abdul Kahar(Science and Engineering Research Centre (SERC), Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Malaysia)