Seaweed biomass derived bio solvents for the large scale production of few layered graphene nanosheets from graphite

Large-scale production of graphene sheets by liquid-phase exfoliation of graphite is a challenging task from a sustainability point of view. Certain bio-derived solvents were found to exfoliate graphite to produce single-layered graphene sheets but the high cost of the solvent is always a deterring factor towards upscaling of the process. Herein, Kappaphycus alvarezii, a cultivable red seaweed is demonstrated as a sustainable resource for producing a bio solvent for exfoliation and to produce graphene sheets from graphite. A solvent system consisting of levulinic acid, acetic acid, and γ-valerolactone was prepared from the polysaccharide obtained from the seaweed biomass through acid hydrolysis under pressure and the mixture was found to exfoliate graphite to produce few-layered pristine graphene nanosheets. The process is scalable and cost-effective and the seaweed biomass-derived solvent mixture can be recovered and reused in the subsequent cycles of exfoliation for large-scale production of graphene nanosheets.