Engineering bacterial pretreatment of basswood for enhanced hydrophobicity and phenolic contaminant removal selectivity of derived biochar

Lignocellulosic biomass-derived biochar (LCB-BC), produced from industrial crops and agricultural residues, is an eco-friendly remediation material with strong commercialization potential due to its renewable feedstock and tunable microstructure. To improve the selective adsorption of hydrophobic contaminants, this study introduces a cost-effective, bottom-up enzymatic modification strategy employing Bacillus subtilis -derived enzymes to selectively depolymerize basswood lignin. This process enriches the cellulose content, guiding the assembly of sp² -hybridized carbon during pyrolysis and significantly enhancing the hydrophobicity of the resulting biochar (BTBC). BTBC exhibits enhanced hydrophobicity and a hierarchical porosity, stemming from short-range graphitic order and partial bacterial delignification, respectively. It demonstrates superior selective adsorption toward phenolic compounds (PCs), with capacities (mg g −1 ) ranking as BPC (465.6) > BPA (351.2) > 2,4-DCP (329.9) > BPF (304.9) > 4-CP (280.3) > BPS (243.1), which positively correlates with their hydrophobicity. BTBC achieves adsorption equilibrium within 45 min, twice as fast as natural biochar. Desorption studies and theoretical simulations confirm that hydrophobic interactions govern its selective adsorption. This work presents a sustainable and scalable strategy for valorizing lignocellulosic biomass into high-performance biochar, paving the way for the development of advanced, carbon-based adsorbents for industrial wastewater treatment. • A novel biochar (BTBC) prepared via Bacillus Subtilis for enhanced hydrophobicity. • The BTBC exhibits selective and high adsorption for phenolic compounds (PCs). • The well-developed porous structure of BTBC boosts PCs adsorption kinetics. • Desorption studies and simulations confirm hydrophobic-driven selective adsorption.