The production of cellulose nanocrystals (CNCs) from vegetable fibres and residues has been intensely investigated due to the properties of high crystallinity and specific surface area of these nanofillers. The most common method of obtaining CNCs is by acid hydrolysis with inorganic acids; however, this method can lead to uncontrolled depolymerisation of the cellulose. Thus, this article examines the use of Lewis acids (FeSO₄, Fe₂(SO₄)₃ and FeCl₃) as co-catalysts in the acid hydrolysis process and compares their impact on the yield, reduction of particle size and crystallinity index of the CNCs. The results show that the presence of Fe₂(SO₄)₃ and FeCl₃ improved the yield (50 and 27%, respectively) and decreased the particle size (632 and 66 nm, respectively) of the CNCs obtained in the hydrolysis process. On the other hand, the crystallinity index values were similar to that of microcrystalline cellulose (MCC), which was probably due to the severe conditions of the hydrolysis process that was used. The scanning transmission microscopy (STEM) images showed a spherical morphology for the CNCs obtained by both inorganic acid and Lewis acids; once again, this was probably due to the severe hydrolysis conditions. Thus, the presence of Lewis acids in the hydrolysis process makes it more efficient because it increases the efficiency of the hydrolysis in a less corrosive environment and with less probability of depolymerisation of the cellulose.

由于这些纳米填料的高结晶性和比表面积，已经从植物纤维和残渣生产纤维素纳米晶体（CNC）进行了深入研究。获得CNC的最常用方法是用无机酸进行酸水解。然而，这种方法可能导致纤维素的失控解聚。因此，本文探讨了路易斯酸（FeSO ₄，Fe ₂（SO ₄）₃和FeCl ₃）在酸水解过程中作为助催化剂的用途，并比较了它们对产量，降低粒径和结晶度的影响。 CNC。结果表明，Fe ₂（SO ₄）_3的存在FeCl ₃和FeCl ₃提高了水解过程中获得的CNCs的产率（分别为50％和27％），并降低了粒径（分别为632和66 nm）。另一方面，结晶度指数值与微晶纤维素（MCC）的结晶度指数值相似，这可能是由于所使用的水解过程的苛刻条件所致。扫描透射显微镜（STEM）图像显示了通过无机酸和路易斯酸获得的CNC的球形形态。再一次，这可能是由于严格的水解条件。因此，水解过程中路易斯酸的存在使其效率更高，因为它在腐蚀性较低的环境中提高了水解效率，并且纤维素解聚的可能性较小。