Lignin-Retentive Hierarchical Aerowood via Partial Dissolution-Regeneration: A Sustainable Strategy for Interfacial...

Organic dye pollution has become one of the most urgent environmental issues worldwide. Wood-based aerogels have been widely applied for dye adsorption owing to their anisotropic and hierarchical porous structures. However, the inefficient utilization of the cell lumina severely restricts their adsorption performance. Herein, Aerowood was converted from natural wood via a low-temperature partial dissolution-regeneration strategy. This process constructs nanofibrillar networks within the wood cell lumina while retaining a significant fraction of lignin, generating a scale-spanning hierarchical porous structure with enhanced interfacial accessibility and efficient mass transport pathways. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation is employed as a representative surface functionalization approach to elucidate the interplay between surface chemistry and physical transport. As a result, Aerowood exhibits excellent water stability and a favorable balance between mechanical robustness (compressive strength of 4.72 MPa) and dye adsorption capacity (83.25 mg·g^-1 for methylene blue and 65.97 mg·g^-1 for crystal violet). Adsorption behavior follows the Langmuir isotherm and pseudo-second-order kinetic model, indicating that monolayer adsorption is governed by surface-related processes. Overall, this work offers fundamental insights into the regulation of hierarchical porous structures and mass transport processes in bioderived porous systems for adsorption.