Conversion of palm oil empty fruit bunches to highly stable and fluorescent graphene oxide quantum dots: an eco-friendly approach

Abstract

Empty fruit bunches, a byproduct of palm oil mills, are currently underutilized despite their potential as a valuable source of biomass for material development. A novel and sustainable method is proposed in this work to produce graphene oxide quantum dots (GOQDs) using empty fruit bunches (EFB) as a starting material. Carbonization of EFB was conducted in a nitrogen atmosphere furnace at temperatures ranging from 30 to 750 °C with a constant heating rate of 10 °C/min, followed by synthesis of GO from the carbonized cellulose using the modified Hummers' method. Subsequently, hydrothermal treatment was employed to synthesize GOQDs from GO, resulting in highly stable and fluorescent GOQDs with an average diameter size of 6.80 nm. The optical properties of GOQDs were characterized by UV–vis spectroscopy, which exhibited a strong absorption at 230 nm, yellow color under visible light, and blue-green luminescence under a 395 nm UV lamp. FTIR spectra confirmed the existence of hydroxyl, carbonyl, and hydrocarbon groups, which originated from lignocellulosic materials and provided excellent water stability and solubility properties to GOQDs. The current study presents an eco-friendly approach to converting biomass waste into materials with outstanding chemical and physical properties that can be applied in various fields.