Sustainable production of value-added chemicals from food waste and forest residues
Date
2025
Authors
Journal Title
Journal ISSN
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Publisher
University of Delaware
Abstract
Over 80% of global energy and more than 90% of chemical products are derived from fossil fuels, making them a dominant driver of greenhouse gas emissions. The escalating demand for energy and chemicals, alongside increasing environmental awareness and stringent greenhouse gas emission regulations, highlights the critical need for renewable alternatives. Forest residues and food waste (FW) are promising resources to meet these demands sustainably. In addition to feedstock selection, a sustainable biorefinery relies on conversion technology, and high-value products while maintaining cost-effectiveness, energy and carbon efficiency. In this thesis, we investigate conversion of FW and forest residues into value-added chemicals via economic and environment-friendly processes. ☐ The extraction of phenolic acids from FW prior to thermocatalytic valorization is crucial for enhancing resource efficiency and economic gains. In Chapters 2-4, we address the key knowledge gaps in phenolic acids extraction from diverse FW feedstocks. In Chapter 2, we establish a blueprint for solvent selection, offering new insights into phenolic acids extraction from FW. A high-performance solvent is identified, and its utility is demonstrated on potato peel waste. In addition, a strategy for replacing highly soluble toxic solvents with green mixtures is presented. Chapter 3 focusses on understanding the impact of feedstock heterogeneity on microwave heating and extractive yields. We demonstrate that the heating of FW-extractant mixtures is unaffected by the FW dielectric properties, as uniform mixing occurs at a 0.05 solid-to-liquid ratio (g/mL). The enhanced heat and mass transfer in high-moisture FW improves target acid yields, governed by the acid’s concentration in free and bound forms. We elucidate intermolecular interactions among various FW components that yield higher phenolics in mixed FW compared to a simple additive model and provides new insights into developing versatile MAE strategies for treating diverse feedstocks. Finally, Chapter 4 presents synthesis of a molecular imprinted polymer to selectively separate commercially valuable phenolic acids from a FW-extracted mixture. A biobased monomer is identified for synthesis of the polymer, providing the highest separation factor for chlorogenic acid compared to traditional monomers. HSPiP is employed to screen synthesis solvents and functional monomers. The data indicates that the extraction solvent interacts with the polymer, influencing its performance. We propose a separation strategy utilizing the synthesized polymer and apply it to potato peel and coffee bean waste extractive mixtures, analyzing its economic and environmental advantages over commercial alternatives. ☐ In chapter 5, we direct our attention to reductive catalytic fractionation of forest residues of three tree parts (bark, twigs/branchlets, leaves) collected in four phenophases (senescence, leafless, emergence, and leafed for deciduous trees) from four co-occurring species (Betula lenta L., Fagus grandifolia Ehrh., Liriodendron tulipifera L., and Pinus rigida Mill). We examine the impact of phenophases, species and tree part on the lignin content, total phenolic monomer, S, and G units yields. Generally, bark has the highest lignin content, followed by twigs/branchlets and leaves. Further, the forest residues collected in leafed phenophase provide the highest total phenolic monomer yields, making them more effective for lignin valorization. This work introduces simple harvesting strategies for targeting specific monomers and products for biorefineries.
Description
Keywords
Extraction, Food waste, Forest residues, Microwave, Molecular imprinted polymer