The doctoral dissertation in the field of Chemistry will be examined at the Faculty of Science, Forestry and Technology, Joensuu campus.
What is the topic of your doctoral research? Why is it important to study the topic?
This study is important for sustainability and maximizing the value of forest resources by finding innovative ways to utilize underused byproducts like tree bark, which currently make up over 40% of Europe's biomass but are mostly burned for basic energy. By converting this waste into valuable, eco-friendly chemicals that can replace less sustainable petroleum-based products, the research not only reduces waste but also creates opportunities for producing specialized chemicals and opens new economic possibilities for the forest industry.
What are the key findings or observations of your doctoral research?
The study explores how pyrolysis can turn tree bark into useful chemicals such as suberinic fatty acids, triterpenoids, and phenolic compounds. Fast pyrolysis is effective and suitable for large-scale use, while slow pyrolysis creates specific chemicals but has challenges like unwanted reactions and extra water in the products. This research demonstrates innovative ways to repurpose underused tree bark into valuable specialty and platform chemicals, reducing waste and environmental impact while supporting the transition away from petrochemical products. By promoting a circular economy and leveraging scalable technologies like fast pyrolysis, the findings offer practical solutions for industrial applications. The study also provides valuable data for optimizing pyrolysis processes.
How can the results of your doctoral research be utilised in practice?
The chemicals found in pyrolysis liquids of tree bark can serve as sustainable alternatives in industries like pharmaceuticals, cosmetics, and materials manufacturing.
What are the key research methods and materials used in your doctoral research?
This research focused on using hardwood bark, particularly birch bark and short rotation tree bark. The main methods used were fast pyrolysis and slow pyrolysis techniques. The solvent extraction and hydrolysis methods were also introduced. Besides, high resolution FT-ICR MS was used to analyze the chemical composition of the pyrolysis liquids.
The doctoral dissertation of Qing Zhao, MSc, entitled Thermochemical biorefining of hardwood bark will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will Dr. Christopher Rüger, University of Rostock, Germany, and the custos will be Professor Janne Jänis, University of Eastern Finland. Language of the public defence is English.
