Joshua Yuan, Energy, Environmental and Chemical Engineering Chair and Lucy & Stanley Lopata Professor

Lignocellulosic biomass is the most abundant renewable energy and biopolymer source. The innovations in biomass utilization have profoundly impacted the advancement of human civilization. The fundamental understanding of the structure-property relationship of biomass polymers empowers biomaterial design to address some of the most daunting challenges in our generation, including global climate change and persistent waste accumulation. Conventional research on biomass utilization focused on reducing lignin content to increase cellulose saccharification in biorefinery, yet the discoveries failed to inform how to manufacture quality biomass-based materials. Recent studies have advanced the understanding of biomass structure–property relationships and discovered several characteristics such as lignin molecular weight, uniformity, linkage profile and functional group that are critical for manufacturing diverse quality biomaterials.

These discoveries have informed the chemical design to produce lignin carbon fiber with highest reported properties. The chemical design of High Molecular Weight Esterified-Linkage Lignin (HiMWELL) empowers lignin to improve carbon fiber performance from polyacrylonitrile (PAN) under the same conditions. Furthermore, the unique HiMWELL design enabled shear-thinning effects when mixed with certain hydrophobic polymers and can introduce UV shielding, enhance mechanical properties, and promote recyclability at the end-life. The research complemented with a grafting process to manufacture lignin-PMMA-ZnO blends, which can have improved end-life recyclability without compromising the mechanical properties. Besides carbon and plastic materials, we also achieved chemical modification to allow lignin to serve as an efficient sorbent for PFAS (Perfluoroalkyl and Polyfluoroalkyl Substances), the forever chemical.

The structure design opened new avenues to design a plant-derived biomimetic nano-framework named as Renewable Artificial Plant for In-situ Microbial Environmental Remediation (RAPIMER). RAPIMER not only exhibits high adsorption capacity for the PFAS compounds, but also provides the substrates for in situ PFAS bioremediation. The lignocellulosic nature of RAPIMER actually promotes fungus growth and bioremediation enzyme expression, due to the presence of lignin as a recalcitrant nature substrate. The material design uniquely enables treatment train integration for recalcitrant hazardous chemicals.

Furthermore, we have recently designed nanocellulose as biofiller to synergistically improve bioplastics mechanical and biodegradable properties. Overall, these studies highlighted that lignocellulosic biomass can be broadly used as a biopolymer resource to design functional materials for addressing energy and environmental challenges.