A Renewable Cellulose Source: Isolation and Characterization of Cellulose Microfibers from Pea Pod Waste

Food industries generate massive waste, which involves environmental and economic problems. The aim of this study was to explore the utilization of agro-industrial wastes, the pea pods, as a source for the production of cellulose microfibers (CMFs). The CMFs were obtained using a chemical alkali extraction and a bleaching treatment. The proximate analysis of the raw material showed that it is composed of 27.3 wt% α-cellulose, 17.3 wt% hemicelluloses and 14.94 wt% lignin, among other components. The yield, α-cellulose content and average diameter of the extracted cellulose were 26.1%, 84.16% and 11 μm, respectively. The removal of most hemicelluloses and lignin from the surface of the fibers was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The degree of crystallinity of CMFs was 63.61%, and the peaks observed in X-ray diffraction patterns refer to the presence of type I cellulose. Thermogravimetric analysis of the extracted cellulose demonstrated its thermal stability compared to the raw and treated materials. Results are promising for taking advantage of these vegetable residues for the isolation of cellulose microfibers and their potential application as reinforcement materials in polymer matrices leading to effective waste management.