Valorization of Lignin Biomass Waste through Lignin Nanoantioxidant Fabrication

This work proposed a facile method to prepare lignin nanosphere antioxidants by self-assembly for the valorization of biomass lignin waste. The technical feasibility of four biomass lignin extractions with choline chloride–lactic acid deep eutectic solvents (DESs) was comparatively assessed. Results showed that the lignin fractionation with DES pretreatment was effective, and the lignin yield reached up to 18.4%. The average particle size of the obtained lignin nanospheres (LNPs) was in the range of 20 ∼ 80 nm at pH = 7. It was proposed that LNPs prepared from deep eutectic solvent technical lignin could be used as promising biodegradable nanoantioxidants with comparable antioxidant ability to natural phenolic compounds. The large number of phenolic hydroxyl groups exposed on the LNP surface benefited its antioxidation performance. This work showed a facile way to prepare lignin nanoantioxidants with DES technical lignin and also provided useful chemical information on the correlation between lignin phenolic hydroxyl groups and its antioxidation ability.