Sustainable valorization of lignocellulosic biomass for the production of chemicals and fuels

The thesis focuses on developing an innovative biorefinery scheme that integrates various catalytic processes—specifically Reductive Catalytic Fractionation (RCF), Aqueous Phase Reforming (APR), and HydroDeOxygenation (HDO)—to produce sustainable energy products like hydrogen, aromatic compounds, and cellulose pulp. The primary aim is to optimize the RCF step to fully valorize lignocellulosic biomass, which includes cellulose, hemicellulose, and lignin. Significant challenges include preventing lignin repolymerization without proper reductive stabilization, achieving simultaneous extraction of hemicellulose and lignin for pure cellulose pulp production, and recovering catalysts from the solid pulp. The research introduces a novel class of magnetic γ-Fe2O3-supported catalysts that effectively address these challenges, enhancing both the yield of lignin oil and the purity of cellulose pulp while facilitating catalyst recovery and reuse. Additionally, the study explores the HydroDeOxygenation of the lignin fraction and APR of hemicellulose-derived fractions using model molecules to determine optimal processing conditions for real biomass streams. The RCF process was tested on industrial waste biomasses, demonstrating scalability through collaboration with ENI Renewable, New Energies and Material Science Research Center. Overall, this work presents a versatile biorefinery scheme aimed at producing key bulk end products essential for the energy transition, emphasizing the importance of optimizing catalytic processes in sustainable biomass conversion.