Synthesis of nanocellulose derived from oil palm empty fruit bunch cellulose via the ultrasound method

Abstract

Oil palm is a major plantation in Indonesia, producing significant waste like oil palm empty fruit bunches (OPEFBs). For every ton of crude palm oil, 1.1 tons of waste are generated. OPEFBs, rich in cellulose, are promising raw materials for nanocellulose production, which has valuable applications in food, cosmetics, and biomedicine. This study investigated nanocellulose production using an ultrasound method (Ultrasonic FS, 300 W), a green and cost-effective technology. The research explored the impact of ultrasonic treatment duration (30, 60, and 90 minutes) on nanocellulose's structure and properties. Nanocellulose was produced from microfibre cellulose derived from OPEFBs. High-resolution transmission electron microscopy (HR-TEM) was used to assess morphology, average diameter, and diameter distribution, while Fourier transform infrared (FT-IR) spectroscopy analysed total crystalline index (TCI), lateral order index (LOI), and hydrogen bond intensity (HBI). Results showed that nano-dimensioned cellulose fibres were observed, and 60 minutes of ultrasonic treatment was optimal, yielding nanocellulose with an average diameter of 8.939 ± 0.714 nm and a diameter distribution of 1-60 nm. While ultrasonic treatment did not significantly affect the TCI value (from 1.0769 to 1.0915), it slightly altered the chemical composition, as indicated by spectral patterns at wavenumbers 3300 cm-1 and 1427 cm-1, showing increased intensity of OH-stretch and CH2 bond (corresponding to the cellulose crystallinity band), correlating with increased HBI (from 0.5890 to 0.9754) and LOI values (from 0.9792 to 1.1394). Thus, the ultrasound method proved to be a promising and efficient approach for synthesizing nanocellulose.