Biproduct to product: Lignin derived from wood and plants could replace fossil fuels in various applications
Biproduct to product: Lignin derived from wood and plants could replace fossil fuels in various applications lead image
Lignins are the organic polymers that provide structure to wood and other plant cell walls. When wood is processed to produce paper, the sturdy lignin is often separated from the cellulose because it yellows and weakens the paper product. This unwanted byproduct of paper-making is called technical lignin.
Because of its abundance, technical lignin is a promising biomass fuel source, while uses for naturally occurring native lignin remain relatively unexplored. Giardino et al. investigated potential applications for both types of lignin.
“The most common place to find technical lignin is in the so-called ‘black liquor’ resulting from paper making,” said author Dunwei Wang. “It is most commonly used as a fuel to be burned or as additives in concrete making.”
Technical lignin can be used in polyurethane foams used in insulation, replacing toxic polyols and increasing flame retardancy.
Without the harsh treatment demanded by paper production, native lignin can be harvested from its natural compound, lignocellulose, using reductive catalytic fractionation. This produces a lignin oil while preserving the more valuable cellulose. Applications for lignin oil include harnessing its antimicrobial properties to combat Staphylococcus aureus bacteria or as a feedstock for polyesters, replacing the fossil-fuel-derived textiles currently on the market.
A significant challenge remains in separating the various chemicals that form lignin. The technical and financial barrier currently limits lignin’s applications, but its demonstrated potential in other areas is cause for hope.
“I am excited that lignin can be extracted from biomass without sacrificing other valuable components,” said Wang. “The prospect of being able to synthesize polymers using a biomass component that is practically a waste is just so exhilarating.”
Source: “From technical lignin to native lignin: Depolymerization, functionalization, and applications,” by Gavin John Giardino, Hongyan Wang, Jia Niu, and Dunwei Wang, Chemical Physics Reviews (2024). The article can be accessed at https://doi.org/10.1063/5.0196825 .
