Lignin is evaluated as a nature-inspired broad-spectrum sun blocker in sunscreen lotions.

Alkali lignin, recovered from the pulping black liquor, was chemically modified by acetylating, and then used as a biomass resource to prepare uniform colloidal spheres via self-assembly. The self-assembled structure and colloid formation mechanism of the acetylated lignin (ACL) were investigated by DLS, SLS, TEM, AFM, XPS, FTIR, elemental analysis and contact angle measurements. Results show that ACL colloidal spheres are obtained from gradual hydrophobic aggregation of ACL molecules, induced by continuously adding water into the ACL–THF solution. ACL molecules start to form colloidal spheres at a critical water content of 44 vol% when the initial concentration of ACL in THF is 1.0 mg mL⁻¹, and the colloidization process is completed at a water content of 67 vol%. An excessive amount of water is added into the dispersions to “quench” the structures formed and then the ACL dispersion is treated by rotary evaporation for recycling THF and acquiring colloidal spheres. The ACL colloidal spheres have an <R_h> of 110 nm with a polydispersity (μ₂/Γ²) of 0.022. The average aggregated number (<N_agg>) in each colloidal sphere and the average density (<ρ>) are estimated to be 1.0 × 10⁵ and 0.187 g cm⁻³. Preparation of water-dispersive lignin nanoparticles opens up a green and valuable pathway for value-added utilization of lignin biomass recovered from pulping spent liquor, which is of great significance for both the utilization of renewable resources and environmental protection.

Developing novel techniques to convert lignin into sustainable chemicals and functional materials is a critical route toward the high-value utilization of lignocellulosic biomass. Lignin-derived carbon materials hold great promise for applications in energy and chemical engineering, catalysis and environmental remediation. In this review, the state-of-art sciences and technologies for controllable synthesis of lignin-derived carbon materials are summarized, pore structure engineering, crystalline engineering, and morphology controlling methodologies are thoroughly outlined and critically discussed. Green chemical engineering with cost-effectiveness and precise carbonization tuning microstructure are future research trends of lignin-derived carbon materials. Future research directions that could be employed to advance lignin-derived carbon materials toward commercial applications are then proposed.

One-step irradiation in a mild solvent caused lignin to be partially depolymerized and π–π disaggregated and thus lignin was largely whitened.