Valorization of Pyrolysis Products Derived from Waste

The demand for sustainable energy and circular resource management is driving research into bio-based and waste-derived materials. In this context, pyrolysis is emerging as an efficient and versatile technology, converting waste into oil, gas, and char fractions that can serve as raw materials for fuels, chemicals, and smart materials. This thesis focuses on valorizing pyrolysis-derived fractions from both lignocellulosic and non-lignocellulosic biomass, as well as plastic waste. Specifically, the first part of the research explores biochar, a solid fraction obtained by slow pyrolysis of biomass sources like hazelnut shells, rice husks, rice grains, and tannery leather shavings. These biochars were transformed into activated carbons to support Pd- and Co-based catalysts. Pd-supported catalysts were applied in benzaldehyde hydrogenation as model reaction to investigate the influence of biochar feedstock on catalytic performance. Activated rice husk biochar (A-RH) emerged as the optimal support. Additionally, co-pyrolyzing rice husk with leather shavings produced a new hybrid material with enhanced catalytic properties and selectivity. Leveraging these insights, Co-based catalysts were synthesized and applied in the hydrodeoxygenation (HDO) of isoeugenol and furfural. These compounds represent the phenolic and furanic fractions of bio-oil, that could be used as alternative source of fuels, especially in the aviation sector. Co/A-RH demonstrated superior activity, attributed to its intrinsic properties and strong interaction with the metal phase, facilitating synergy between Co⁰ and Co²⁺ species. Lastly, part of this research targeted plastic-derived chars, successfully converting them into carbon monoxide via the Boudouard reaction, improving the carbon balance in chemical recycling of plastics and contributing to carbon capture and reutilization. Overall, this thesis highlights the transformative potential of waste-derived materials in catalysis, supporting sustainable fuel production and offering viable strategies for enhanced circular resource utilization.