The full use of biomass plays a central role in transition to a circular bioeconomy. Unlike non-biobased adsorbents, which are criticized for high production costs and the generation of secondary pollutants, lignin nanoparticles (LNPs) are a cost-effective and environmentally benign alternative for water treatment. In this study, LNPs were demonstrated for the first time as multifunctional materials for the adsorption and UV-light driven photocatalytic degradation of methylene blue dye (MB) in water