Table 3.

Categories of lignin-derived products and their applications.

Category	Type	Products	Applications	References
Aromatic macromolecules and fine Chemicals	Klason (Kn), kraft lignin (KL), organosolv (OGs)	Lignin monomers and dimers, aromatic phenols, alkyl phenols, aromatic aldehydes, aromatic alcohols, acids, aryl ketones, antioxidants, dispersants, polyurethanes, phenolic resins, vanillin	Industrial chemicals, bio-based adhesives, multifunctional materials, building blocks for bio-based products	[145]
Polymer and nanomaterials	KL, OGs, straw lignin (SL)	3D printing resin (cationic surfactant), scaffolds, lignin nanotubes, hydrogels, lignin nanotubes	Biomedical applications, tissue engineering, drug delivery	[147]
Carbon materials, biofuels	KL, sulfite, soda, OGs	Biochar, bio-oil, syngas, activated carbon, carbon fibers, carbon black	Light-weight polymer composites, adsorbents, electrochemical devices, automotive	[148]
Specialized applications	KL, sulfite, soda, OGs	Soil conditioner, controlled release agent in fertilizers and pesticides, sequestering agent, contaminant absorbent, fire retardant	agriculture, textiles, soil reclamation, water purification, fire suppression	[145]