Mechanistic insight and consequence of phosphogunstic acid in corncob hydrolysis process

Corncobs were treated with the hydrothermal method using phosphotungstic acid as a catalyst, and furfural and 5-HMF were produced and analyzed using high-performance liquid chromatography (HPLC). The adsorption capacity of corncob residues for methylene blue was also studied. The structure and properties of corncob residues were characterized by the elemental analyzer, X-ray powder diffraction, specific surface analyzer, and scanning electron microscopy. The effects of the dosage of phosphotungstic acid, reaction time, temperature, and solid-liquid ratio on the yields of furfural and 5-HMF were investigated. The yield of furfural reached 26.23% when corncobs were treated with 0.4 g phosphotungstic acid at 160 °C for 4 h. At the same temperature, the smaller solid-liquid ratio could increase the yields of 5-HMF and furfural. The yield of corncob residues varied from 35.95% to 80.80% under different conditions. The adsorption capacity of corncob residues for methylene blue ranged from 9.0 to 57.4 mg/g. © 2020 Elsevier Ltd