| Abstrakt: |
Process conditions influence cellulose nanoparticle properties and their potential applications. A non-catalyzed formic acid-based treatment (NFAH) with an inherent formic acid recycling was assessed as an alternative to conventional sulphuric acid-based treatment (SAH) for producing spherical cellulose nanocrystals (CNC) from unbleached mango seed husk pulp (UMP). The UMP was a product of a two-stage pre-treatment of alkaline and high-shear homogenization-assisted organosolv for hemicellulose and lignin recoveries. The NFAH was optimized via a response surface methodology based on acid-to-pulp ratio (20:1–40:1 mL/g) and time (6–10 h) variations to maximize CNC (FCNC) yield, crystallinity (CrI) and formate content while minimizing particle size. The FCNC yield was approximately 55% higher and 17% more thermally stable (361 °C vs 309 °C) than sulphuric acid-based CNC (SCNC). The optimum formic acid-to-pulp ratio (30:1 mL/g) and time (8 h) resulted in 64% FCNC yield with crystallinity, formate content, particle size, and polydispersity index of 66.40%, 0.92 mmol/g, 24.13 nm and 0.488, respectively. Furthermore, the FCNCs were spherical vs. the rod-like SCNCs. Therefore, NFAH has many advantages over SAH including thermal stability and spherical morphology that would allow for more novel and sensitive applications such as biomedicine. [ABSTRACT FROM AUTHOR] |
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