Synthesis and Characterization of Nanocrystalline Cellulose from Waste Cassava Pulp

In this study, nanocrystalline cellulose (NCC) was synthesized using mixed H ₂ SO ₄ /formic acid hydrolysis from waste cassava pulp produced in Northern Mindanao, Philippines. The study investigated the extraction yield with respect to acid concentration, hydrolysis temperature, and time; the optimal set of such factors; and the characteristics of the optimized NCC. The raw material was pretreated with 4 wt% NaOH and bleached with 4% (w/v) NaOCl. Hydrolysis conditions were formic acid concentration of 50–88 wt%, temperature of 70–90°C, and time of 1–6 hours. Five (5) wt% H ₂ SO ₄ was also added as a catalyst. Based on the results, increased factor values contributed to higher extraction yields, but too much resulted in a decrease. Optimization resulted in the set of factors (71 wt% formic acid, 77°C, and 3.6 hours) with a yield of 67.272% ± 2.295%. FTIR analysis indicated effective removal of lignin and hemicellulose during the pretreatment. Furthermore, SEM images and DLS indicate nano-size dimensions with hydrodynamic diameters from 15 nm to 687 nm and a zeta potential of -14.3 mV. The NCC produced in this study has been found to have comparable extraction yield as previously reported with smaller reported hydrodynamic diameters and less tendency for self-aggregation.