Extraction and Characterization of Cellulose from Coffee Husk and Brewery’s Spent Grain Fibers Using Alkali-Hydrogen Peroxide Treatment Method

Coffee husk (CH) and brewery spent grain (BSG) fibers are sustainable industrial residues that consist of cellulose. The present study aimed at the extraction of cellulose from CH and BSG fibers and to study the effect of alkali-hydrogen peroxide (5% NaOH–7% H₂O₂) treatment during the extraction by characterizing the extracted cellulose. Characterization of cellulose particles, such as crystallinity, functional groups, thermal properties, and morphology, was conducted by performing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), and scanning electron microscopy (SEM), respectively. The finding shows that the maximum cellulose yields obtained from CH and BSG fibers are 37.3% and 26.5%, respectively. From the XRD results, the cellulose obtained from CH fiber (C-CH) and from BSG fiber (C-BSG) showed diffractive peaks with the highest intensity of approximately 1,003 and 1,236 counted at 2θ = 22°, respectively. A reduction in the absorption of peaks was observed on the FTIR spectrum for both C-BSG and C-CH samples at different wavelengths. SEM demonstrated that the surface roughness of the celluloses was enhanced. TGA showed that the maximum temperature decomposition observed for both C-CH and C-BSG is 360°C and 380°C, respectively. Generally, in this study, alkali-hydrogen peroxide (5% NaOH–7% H₂O₂) treatment was effectively used for the treatment of BSG and CH fibers for the extraction and surface modification of cellulose particles. The extracted cellulose in the present study can be used as an alternative to conventional cellulose for the manufacturing of biocomposite materials, preparation of particle boards and furniture, and production of food packaging materials.