Effect of ground wood particle size on biomass fractionation using p-toluenesulfonic acid treatment

Size reduction of biomass is an energy-extensive operation for biorefinery, and fundamentals of size effect on biomass fractionation is pressing to be unraveled. Herein, we investigated effect of ground wood particle size on properties of biomass fractionation using p-toluenesulfonic acid (p-TsOH) treatment. Both carbohydrates and lignin dissolution increased with smaller ground wood particle size. Comparatively, delignification performance was much affected by ground wood particle size, and the percentage of lignin dissolution was dramatically enhanced at small ground wood particle size. The excellent delignification selectivity was warranted at small ground wood particle size accordingly. In addition, mechanism of ground wood particle size effect on lignin dissolution was proposed. On one hand, dissolution of lignin by p-TsOH primarily was an aggregation effect, and diffusion of lignin from the microfibril network in biomass became growingly troublesome at large size. On the other hand, depolymerization of lignin mainly occurred in the liquid phase, which essentially led to production of large p-TsOH-lignin aggregates with low diffusivity.