Wheat bran is an abundant source of cellulose and is still going to waste because of the lack of knowledge about its further exploitation and comprehensive utilisation. Here, cellulose nanocrystals (CNC) were prepared from wheat bran via sulfuric acid hydrolysis. The effects of hydrolysis time on the morphology, surface charge, yield, structure, thermal stability, physicochemical properties, and cytotoxicity of CNC were investigated. Results showed that non-cellulosic components were extensively removed by the purification process. Transmission electron microscopy confirmed that the obtained CNC displayed a needle-like shape with various dimensions. Zeta potential values of the CNC suspensions ranged from -36.5 to -39.8 mV. A hydrolysis time of 60 min resulted in CNC with the highest crystallinity (70.32%). The thermal stability of CNC shifted to lower temperature with increasing hydrolysis time. In addition, the obtained CNC exhibited interesting physicochemical properties (the water/oil retention capacities and the adsorption capacities to heavy metals) and good biocompatibility, suggesting their great potential as reinforcement for the manufacture of nanocomposites.
Keywords: Cellulose nanocrystals; Cytotoxicity; Wheat bran.
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