Lignin Recovery and Lignin-Based Products
An overview is given of the recovery and use of wood lignin. Most of the lignin produced today is lignosulfonate from sulfite pulping processes. Lignin from the more common kraft pulping process is also becoming available due to new technology. Another industrial source is as a byproduct from wood-based ethanol production. Isolated lignin can be refined into high-quality biofuel or used as raw material for materials and chemicals. Today, the most common use of lignin is in applications as dispersing/emulsifying agents or as adhesives/binders. Possible future applications for polymeric lignin is carbon fiber, activated carbon, polyurethanes, adhesives and complexing agents. The lignin macromolecule can also be depolymerized into phenolic monomers for the production of phenols or other aromatic compounds.