Facile and economical, single-step single-chemical method for conversion of palm oil fuel ash waste into graphene nanosheets

Palm oil fuel ash (POFA) is a waste material generated in large quantities by palm oil industry worldwide. To avoid the rising disposal costs and environmental issues, its positive and cost-effective utilization is the urgent requirement. An economical, single-step, and green chemical method has been adopted in this study to convert as received waste byproduct, POFA, from oil palm mills to produce precious "POFA derived graphene (PDG) nanosheets." The results analyses from different latest instrumental techniques like Raman, High-resolution transmission electron microscopy (HRTEM) and Atomic force microscopy (AFM) confirmed the successful synthesis of 1–8 layer PDG nanosheets with high yield (> 25 wt%). Parameters like temperature, the ratio of KOH: POFA, and reaction time were optimized to get the maximum yield and removal of all inorganic impurities up to < 0.5 wt.% in the final sample. Clean and smooth edges of PDG with hexagonal rings were also observed using HRTEM. In addition, the surface area of PDG was improved up to 1506.60 m2/g along with a high degree of porosity. Waste POFA ash as the cheapest carbon precursor used for the first time to synthesize economical graphene using a single-step, single chemical method. As a low cost carbon source, POFA, proves to be economical for scalable and sustainable production of PDG and presents an environment-friendly approach towards a green environment, besides promoting the circular economy concept.