The aim of the work was to use an industrial bio-residue as a raw material for the production of cellulose nanocrystals. The used residue, obtained from a bioethanol pilot plant, was purified using chemical extraction and whitening, and separated to nanocrystals by mechanical and chemical treatments such as ultrasonication, high-pressure homogenization and hydrolization. The chemical compositions and characteristics of the bio-residue were studied before and after purification using a TAPPI standard, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The morphology of the isolated nanocrystals was characterized using atomic force microscope (AFM). The chemical composition of the used bio-residue was found to be 49.5 wt-% cellulose, 42.1 wt-% lignin and 8.4 wt-% extractives. The crystallinity of the bio-residue was 14.5% and it increased to more than 73% after the purification process. The AFM study showed that a simple ultrasonication and homogenization processes resulted in nanosized crystals with diameters in the 10-20 nm range.
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