Effects of cellulase treatment on properties and functional performances of hardwood-like lignocellulose-based biochar and its modified derivatives.

Abstract

Treating lignocellulosic agricultural wastes with cellulase generates monosaccharides for biofuel production and saccharification residues that can be converted into biochar with better performance than those from untreated materials. However, while cellulase pretreatment is highly effective for gramineous straws, its efficacy on hardwood-like lignocellulosic materials remains unknown. This study explored the applicability of cellulase pretreatment to tobacco stalks (hardwood-like) for biochar preparation. Results showed cellulase pretreatment enhanced biochar stability and subsequent optimization via thermal air oxidation and colloid modification further improved its performance, confirming it as a high-quality precursor biochar. Cellulase pretreatment primarily increased raw material crystallinity, which in turn improved biochar crystallinity and structural stability. Compared with untreated biochar (BC-O), colloid-modified biochar (BC-SAC) exhibited a rise in specific surface area from 4.9 to 344.1 m2/g, alongside rapid phenol adsorption reaching equilibrium within 12 h and enhanced removal performance toward various phenolic contaminants. Environmental and economic evaluations indicated that BC-SAC achieved a carbon emission reduction of 0.68 t CO2 per year per ton of feedstock. Additionally, its iodine value, a key pricing index for carbon-based adsorbents, rose from 503 mg/g to 881 mg/g. This study broadens the feedstock scope of cellulase pretreatment for biochar production and is of great significance for efficient multi-product utilization of lignocellulosic biomass resources.