Olive Tree (Olea Europaea) Pruning: Chemical Composition and Valorization of Wastes through Liquefaction

Olive tree branches (OB) and leaves (OL) from the Viseu region (Portugal) were studied for their chemical composition and liquefaction behavior using polyalcohols. Chemical analysis revealed that OL contains higher ash content (4.08%) and extractives, indicating more bioactive compounds, while OB has greater α-cellulose (30.47%) and hemicellulose (27.88%). Lignin content was higher in OL (21.64%) than OB (16.40%). Liquefaction experiments showed that increasing temperature from 140°C to 180°C improved conversion, with OB showing a larger increase (52.5% to 80.9%) compared to OL (66% to 72%). OB reached peak conversion faster, and optimal particle size for OB was 40-60 mesh, while OL performed better at finer sizes. OL benefited more from higher solvent ratios, whereas OB achieved high conversion with less solvent. FTIR analysis confirmed that acid-catalyzed liquefaction breaks down lignocellulosic structures, depolymerizes cellulose and hemicellulose, and modifies lignin, forming hydroxyl, aliphatic, and carbonyl groups. These changes reflect progressive biomass degradation and incorporation of polyalcohol components, converting solid biomass into a reactive, polyol-rich liquid. The study highlights distinct chemical and processing characteristics of olive branches and leaves, informing their potential industrial applications.