Functional valorisation of forest derived lignocellulosic waste with high sorption rate and pH stability

Lignocellulosic residues derived from forest and agricultural systems represent an abundant and underutilised biomass stream with potential applications in water treatment. In this study, a comparative screening of selected lignocellulosic materials (oak sawdust, glans peduncles, barley straw, camelina straw, and flax/hemp dust) was performed for the removal of bisphenol A (BPA) from aqueous solutions, with activated carbon used as a reference. All investigated materials exhibited rapid adsorption, with equilibrium uptake of 90-95% achieved within 3 min and equilibrium approached within ~ 30 min under the studied conditions. Adsorption kinetics were well described by the pseudo-second-order model (R² = 0.996-0.999), although this is interpreted as a descriptive fit rather than direct evidence of chemisorption. Oak sawdust and glans peduncles showed the most stable performance across the tested pH range (3-11). The study has a screening character and was conducted at elevated BPA concentrations (20-500 mg/L) to enable kinetic analysis. Therefore, the results provide a comparative and mechanistic basis for further investigation rather than direct evidence of environmental or industrial applicability. The pHpzc analysis suggests that sorption is not controlled solely by electrostatic interactions; instead, specific interactions related to lignin-rich domains-such as π-π interactions, hydrogen bonding, and hydrophobic effects-play a substantial role. The results highlight the importance of structural and chemical characteristics of woody biomass in determining functional performance under aqueous exposure and emphasise the potential of oak-derived residues as stable, sustainable materials contributing to the valorisation of forest resources.