Sustainable production of cellulose nanofibers and nanopaper sheets from olive pomace waste through mechanical defibrillation

This study investigates the utilization of olive pomace to produce cellulose nanofibers (CNF) for manufacturing nanopapers. The adopted method for extracting cellulose fibers and CNF involved alkaline and bleaching treatments, as well as a mechanical defibrillation process. CNF were obtained by a TEMPO-mediated oxidation pretreatment followed by grinding. Initially, the chemical constituents of olive pomace were analyzed using various analytical techniques. The morphological, crystalline, and thermal properties of CNF were assessed and used for making nanopaper sheets. The optical and physical properties of the nanopaper sheets were evaluated using standard methods. The isolated CNF had average width and length values of 20.80 nm and 341 nm, respectively. The nanofibers exhibit a thermal degradation onset temperature of 242 °C and a crystallinity of 60.6%. Nanopapers made from CNF showed a tensile strength of 6.07 MPa, an elongation at break of 2.49%, Young’s modulus of 8.04 GPa, and a water vapor permeability of 7.95 g.µm/m².d.kPa. Overall analysis of the results confirmed that the produced CNF displayed favorable physical and optical properties. Therefore, olive pomace emerges as a valuable source for producing high-quality CNF for nanopaper manufacturing.