Effect of Alkali Concentration on the Nanofibrillation Efficiency of Cellulose by Mechanical Grinding

Abstract

Efficient production of cellulose nanofibers (CNFs) from wood pulp remains a challenge for industrial applications, requiring optimized pretreatment and processing strategies. In this study, hardwood kraft pulp (Hw-BKP) was pretreated with NaOH solutions (5 to 20 wt%) and subsequently processed using a large-scale wet grinder. The effects of pretreatment concentration and grinding on nanofibrillation efficiency were evaluated through compositional, structural, and optical analyses. Alkali pretreatment promoted hemicellulose removal and crystalline transforma-tion, while mechanical grinding facilitated progressive microfibrillation. Notably, pretreatment at concentrations above 15 wt% significantly enhanced nanofibrillation efficiency, highlighting the importance of crystalline transformation in addition to hemicellulose removal. These findings provide practical insights for optimizing CNF production processes and advancing their industrial-scale commercialization.