Characterization of physicochemical properties and techno-economic analysis of cellulose nanocrystals derived from pilot production of sweet potato residue

Cellulose nanocrystals (CNCs) have attracted great interest because of the unique structural characteristics and physical and chemical properties, but their high cost limited the application. The purpose of this study was to achieve the pilot-scale production of cellulose and CNCs by using sweet potato residue (SPR) as the main raw material. Meanwhile, based on the process of preparing CNCs from commercial acid hydrolyzed wood, a systematic economic benefit comparison was conducted on the production of CNCs from SPR. The results showed that the degree of polymerization of the cellulose produced was 475. CNCs was produced from SPR cellulose, and the CNCs had a rod-like structure, with the diameter and length ranging from 15.10 to 30.90 nm and 80.80-259.90 nm respectively. CNCs was a type I cellulose structure with high crystallinity, and the introduction of the amine characteristic peak (1665 cm- 1) proved the successful production of CNCs. The maximum thermal degradation temperature of CNCs was 347.88 degrees C, and the zeta potential was -40.07 mV, which made it suitable for use as a reinforcing material in environmental protection bio-composites. The total capital investment to produce commercial CNCs was $227.74 million, while the total capital investment for CNCs from SPR was $203.34 million. Compared with commercial CNCs, the trial production of CNCs was more financially profitable and its net present value was higher. The use of SPR had both economic and environmental benefits, reducing the use of fossil fuels. These results are helpful in guiding the high-value utilization of other agricultural by-products and the further development of CNCs composites.