Valorization of corn cob toward multipurpose fractionation with a recyclable acid hydrotrope: furfural, phenolic compounds, and pulp

In this study, a strategy of corncob valorization was proposed. Corncob was first pretreated with a recyclable acid hydrotrope (p-TsOH, aqueous solution) to selectively remove lignin and hemicelluloses. After pretreatment, the collected liquid phase was diluted with deionized water to precipitate lignin. The hemicelluloses degradation products, mainly pentose, in the resulting acid liquor were converted into furfural with a yield of 53.65% without adding any catalyst. The collected lignin was depolymerized to phenolic monomers with a yield of 68.00% via a hydrodeoxygenation process. The pretreated cellulose-rich solid was subjected to 10 s ultrasonic treatment to form pulp and subsequently used for papermaking by blending it with commercial softwood pulp. With a corncob pulp addition of 20%, the tensile index and ring crush index of hand sheets increased by 10.62% and 5.05%, respectively, compared with those containing 100% softwood pulp. Therefore, this study provided a strategy for corncob valorization toward multipurpose fractionation: furfural, phenolic monomers, and pulp, reaching a comprehensive utilization of corncob.