Valorization of lignocellulosic biomass for non-fossil chemicals and fuels using photolysis based on LED

Research Project, 2020 – 2023

Sawdust, a valuable lignocellulosic biomass, is today considered waste and burnt to generate heat. Depending on the sawing process, sawdust might be up to 50% of the timber. An energy efficient valorization of lignocellulosic waste into non-fossil chemicals and fuels minimizes the CO2 footprint and contributes to a sustainable production. A major challenge is to decouple the biomass into basic building blocks. This conversion is at present based on processes that operate at high temperatures and pressures, resulting in a complex mixture in the process liquor, and consuming huge amount of heat.

We propose a conversion process based on UV light from energy saving LEDs through photolysis consuming less energy. Preliminary results indicate that irradiation of lignin or cellulose dispersed in water at 254 nm broke the β-O-4 bond in lignin while cellulose stayed intact. Lignin has various bonds with different bond dissociation energies, which could be broken selectively by a specific wavelength, forming functional products. We will map the cleaved and newly formed bonds at different wavelengths for different lignins and cellulose in different solvents. Solutions will be analyzed with standard methods while the solid materials will be analyzed with novel dynamic nuclear polarization solid-state NMR. Within 4 years, we expect to understand the underlying photochemistry to form high value chemicals and fuels from lignocellulosic waste energy- and resource efficiently.