Efficient delignification of wheat straw by induced electric field-assisted alkali pretreatment

In this study, the effectiveness for induced electric field-assisted alkali pretreatment (IEF-AAP) of wheat straw (WS) was evaluated and compared with hydrothermal assisted alkali pretreatment (HT-AAP). The influence of IEF-AAP and HT-AAP on enzymatic hydrolysis of WS based on physico-chemical changes were investigated. The maximum lignin and hemicellulose removal of residual WS after IEF-AAP were 78.9 % and 70.0 %, remarkably higher than that of HT-AAP (74.4 % and 60.6 %), which can be explained by the electrical effect. The optimized IEF-AAP conditions were alkali concentration 1.5 %, temperature 80 °C and duration 3 h. Under optimized conditions, the enzymatic efficiency of WS after IEF-AAP was 79.7 %, while that after HT-AAP was 74.9 %. The surface morphology, functional groups, porosity characteristics, crystallization as well as thermal stability of residual WS after IEF-AAP and HT-AAP were analyzed. It was found that electrothermal pretreatment had more pronounced effect on the physicochemical properties of WS, mainly manifested as complex morphological structure and pore properties. There was no obvious difference between the lignin prepared by the two processes. Induced electric field, as a novel electrotechnology, has shown potential in the pretreatment of lignocellulose. It also provides an idea for the development of new preprocessing strategies.