Preparation of cellulose nanocrystals from empty fruit bunch of palm oil by using phosphotungstic acid

Empty fruit bunch (EFB) of palm oil, an abundant agro-waste in Indonesia, was used as raw material of Cellulose Nanocrystals (CNCs) preparation. Instead of conventional acid mineral, phosphotungstic acid (H3PW12O40, HPW) was used to hydrolyze cellulose due to recycling ability and easy handling. Before hydrolysis process, dried EFB was treated by 3% NaOH solution at 90 degrees C for 2 hours and then bleached using 2% NaClO2 solution at 80 degrees C for 3 hours to remove hemicellulose and lignin. Hydrolysis reaction parameters such as temperature, acid concentration, and reaction time were optimized with fixed solid-liquid ratio of 1: 40. Response surface method was used for experimental design to determine the optimum condition of each parameter by using software Minitab. In this study, pulp from dried EFB produced 44.8% yield of CNCs. Dynamic Light Scattering (DLS) analysis showed that most of CNCs equivalent diameter was 140 nm. Crystallinity index was observed at 73.3% using X-ray Diffraction (XRD) analysis. Thus, a green established process for the preparation of CNCs was achieved.