Mathematical Modeling of the Solid-Liquid Extraction of Phenolic-Rich Compounds from Pinus contorta Bark

There is an ongoing effort to replace traditional wood adhesives with tree bark-derived resins that use an underutilized biomass residue (tree bark) to reduce the consumption of petroleum-derived chemicals for economic and environmental benefits. A key step in bark-to-resin conversion involves the reactive solid-liquid extraction of phenolic-rich compounds from bark by a caustic solvent. Despite significant work concerning bark conversion, efforts to understand this process were mostly empirical investigations. Therefore, this thesis focuses on developing mechanistic models for the solid-liquid caustic extraction and comparing theoretical predictions with experimental data. Among five types of kinetic behaviour models, it was found that the extended Fick's law most accurately described the process. Isotherms were proposed to model equilibrium, which was found to have the best fit with the BET isotherm. This thesis work provided valuable insights into the extraction process mechanism that will help with future improvement in equipment design and scaling-up studies.