Use of Ionic Liquid in Different Routes for Obtaining Nanocellulose from Yerba Mate Residues

The aim of this work is to evaluate different methods of obtaining nanocellulose from an agro-industrial residue, using yerba mate sticks (YM) as raw material, through chemical and mechanical processes, such as bleaching (B), ionic liquid (IL) and steam explosion (S). Nanocellulose was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The XRD results showed that the samples YM-SBIL and YM-SIL presented 50.23% 43.06% of crystallinity for cellulose II, respectively. FTIR of YM-SIL showed peaks with greater intensity in regions related to bonds from cellulose II, also seen by TGA. DLS results demonstrated that the size distribution below 100 nm was above 60% in all treated YM samples. Steam explosion, bleaching and IL treatments brought the YM fibers closer to the characteristics of commercial cellulose fibers (CC), suggesting that the treatments were effective in reducing components such as hemicellulose and lignin. The addition of the chemical bleaching did not show considerable differences to the IL treatment, indicating that IL can be a viable option for obtaining nanocellulose.