Strong adsorption enhances mass transfer and promotes efficient hydrolysis of cellulose to sugar by solid acids

Efficient conversion of cellulose to glucose is a crucial challenge for the energy and materialization of non-food biomass. Solid acids' adsorption strength is essential to affecting mass transfer efficiency. In this study, solid acids with different particle sizes (from 0.25 to 10.10 μm) modified with -OH and -PO₃H₂ were obtained by hydrothermal method. Hydrolysis of cellulose at 180 °C for 4 h revealed that the particle size of the solid acids was directly proportional to the cellulose conversion (R² = 0.925). Still, there was no significant correlation with the glucose yield (R² = 0.632). Eventually, the cellulose conversion reached 98.9 %, with a 30 % glucose yield. The solid acids demonstrated good stability and recoverability. This study fills the gap in the influence of solid acid particle size and reveals the mechanism of strong adsorptive mass transfer and hydrolysis efficiency. It provides the theoretical basis for the design of high-performance solid acids.