Sustainable production of cellulose nanocrystals from sugarcane bagasse via statistically optimized acid hydrolysis

Cellulose nanocrystals (CNCs) were successfully produced from sugarcane bagasse (SCB) through acid hydrolysis with statistically optimized parameters using Central Composite Design (CCD). SCB, comprising 30–40 wt% of sugarcane by-products, offers an eco-friendly cellulose source without compromising food supply. The process involved mechanical, alkaline, and bleaching pretreatments to remove lignin and hemicellulose, followed by sulfuric acid hydrolysis. Process parameters are acid concentration 45–65 wt%, temperature 45–60 °C, and duration 30–60 min were optimized using CCD. The authors achieved a maximum CNC yield of 42% at 61.25 wt% acid concentration, 58.2 min, and 45 °C. Characterization confirmed successful CNC production: 90% of particles were nanoscale with 102.6 nm average diameter. SEM revealed rod-shaped morphology, while FTIR spectra showed progressive attenuation of characteristic lignin and hemicellulose peaks, consistent with their removal during pretreatment. XRD analysis showed crystallinity improvement from 44.7% (raw SCB) to 70.01% (CNCs). DSC demonstrated enhanced thermal stability with decomposition at approximately 335 °C. This study highlights the effectiveness of combining acid hydrolysis with statistical optimization for high-yield CNC production from agricultural waste. The sustainable valorization of SCB offers promising applications in bio-composites, packaging, and advanced nanomaterials.