Process intensification via probe sonication in protic ionic liquid pretreatment of biomass

• Probe sonication was employed to accelerate biomass fractionation during protic ionic liquid pretreatment. • The acceleration effect of sonication was found to be feedstock-dependent, exhibiting higher efficiency and durability with the more recalcitrant softwood (spruce). • The uneven spatial distribution of acoustic energy during sonication resulted in cellulose-rich pulps with heterogeneous particle sizes. • Quantitative analysis revealed that the primary cause of acceleration was the sonication-induced temperature increase rather than the enhancement of mass transfer.