Higher efficiency of vanadate iron in heterogeneous Fenton-like systems to pretreat sugarcane bagasse and its enzymatic saccharification.

Abstract

Pretreatment is crucial for effective enzymatic saccharification of lignocellulose such as sugarcane bagasse (SCB). In the present study, SCB was pretreated with five kinds of heterogeneous Fenton-like systems (HFSs), respectively, in which α-FeOOH, α-Fe₂O₃, Fe₃O₄, and FeS₂ worked as four traditional heterogeneous Fenton-like catalysts (HFCs), while FeVO₄ worked as a novel HFC. The enzymatic reducing sugar conversion rate was then compared among SCB after different heterogeneous Fenton-like pretreatments (HFPs), and the optimal HFS and pretreatment conditions were determined. The mechanism underlying the difference in saccharification efficiency was elucidated by analyzing the composition and morphology of SCB. Moreover, the ion dissolution characteristics, variation of pH and Eh values, H₂O₂ and hydroxyl radical (·OH) concentration of FeVO₄ and α-Fe₂O₃ HFSs were compared. The results revealed that the sugar conversion rate of SCB pretreated with FeVO₄ HFS reached up to 58.25%, which was obviously higher than that under other HFPs. In addition, the surface morphology and composition of the pretreated SCB with FeVO₄ HFS were more conducive to enzymatic saccharification. Compared with α-Fe₂O₃, FeVO₄ could utilize H₂O₂ more efficiently, since the dissolved Fe³⁺ and V⁵⁺ can both react with H₂O₂ to produce more ·OH, resulting in a higher hemicellulose and lignin removal rate and a higher enzymatic sugar conversion rate. It can be concluded that FeVO₄ HFP is a promising approach for lignocellulose pretreatment.