Controlling the self-assembly behaviors of soluble lignin oligomers is key to construct uniformly spherical lignin nanoparticles (LNPs) and benefit to their specific applications. Herein, several H₂O-organic solvent systems were selected for solvolysis of the lignin in wood chips to obtain the lignin oligomers with different structural features. Afterwards, the reaction liquors containing soluble lignin oligomers were employed to produce LNPs via continuous adding H₂O. The self-assembly behaviors of the lignin oligomers were strongly influenced by the structural features of the lignin oligomers and the existing organic solvents. From solvothermal extraction in H₂O-polar aprotic solvents (e.g. tetrahydrofuran, acetone, and γ-valerolactone), the lignin oligomers with widely-ranged molecular weight could self-assemble into regular-shaped and spherical LNPs, making use of every single space. Besides, the conjugated aliphatic side chains with benzene rings and the abundant negative charged groups of the lignin oligomers favored their self-assembly into LNPs with core–shell structures, and the resultant high electric surface charge prevented further aggregation of LNPs into irregular-shaped clusters. Conversely, the existing polar protic solvents (e.g. ethanol and ethylene glycol) and polysaccharides-derived chemicals, dispersed the lignin oligomers and restrained their π–π stacking induced self-assembly via generating undesirable hydrogen bonds. Therefore, ascertaining the ripple effects of the organic solvents on the whole fabrication process of LNPs benefits to control the morphology of LNPs for various applications.

With the rapid growth in the global population and the accelerating pace of urbanization, researching and developing novel strategies for biomass utilization is significant due to its potential for use in renewable energy, climate change mitigation, waste management, and sustainable agriculture. In this environmental context, this review discusses the recent advances in biomass conversion technologies for biochar production, including the first carbonization process and the subsequent activation methods of the biochar derived from lignocellulosic biomass (LBC). Parallel to this, this review deals with other essential parameters in biochar production, such as feedstock types, reaction environments, and operating conditions in the pyrolysis process, to determine the production and composition of LBC. Moreover, the wide-ranging applications of LBC in areas such as adsorption, catalysts, and energy storage are discussed, offering sustainable and environmentally friendly alternatives while reducing reliance on traditional energy sources and mineral resources, thereby providing practical solutions to environmental and energy challenges. Overall, this review not only provides a comprehensive comparative analysis of different LBC preparation methods, but also facilitates a deeper understanding of the advantages and limitations of these methodologies when it comes to developing high-value materials for sustainable applications.

Biomass-derived aldehyde tanning agents with in situ dyeing properties (BAT-iDP) showed excellent tanning-dyeing performance enabled by multipoint cross-linked/conjugated Schiff-base structures.