麦草组分水热-乙醇两步法处理过程中木素在纤维表面的沉积形态

Investigation of Lignin Deposition Morphology on the Fibers of Wheat Straw Subjected to Hydrothermal-Ethanol Two-Step Fractional Separation

关键词:  麦草  水热处理  乙醇处理  木素包覆

Key Words:wheat straw  hydrothermal treatment  ethanol treatment  lignin coated

摘要:本课题通过研究水热-乙醇两步法对麦草组分分离效果的影响，采用场发射扫描电子显微镜、原子力显微镜和X光电子能谱研究了木素沉积形态的变化。结果表明，水热-乙醇两步法对半纤维素脱除率高达94.2%，但是其木素的脱除率仅为41.5%；这与木素在纤维表面发生了沉积这一现象有着密不可分的关系，水热处理后部分木素以颗粒状形式沉积在固相残余物表面，而这一部分沉积的木素并不能在乙醇法处理后溶解，第二步的乙醇法处理改变了沉积木素的形态，将颗粒状木素转变为包覆层吸附在纤维表面，导致了水热-乙醇两步法对木素的脱除率较低。

Abstract:In this paper, the effects of hydrothermal-ethanol two-step treatment on the separation of wheat straw components were studied, and the changes of lignin deposition morphology were investigated by field emission scanning electron microscope, atomic force microscopy and X-ray photoelectron spectrometer. The results showed that the removal rate of hemicellulose by hydrothermal-ethanol two-step process was as high as 94.2%, but the removal rate of lignin was only 41.5%; it was closely related to the deposition of lignin on the surface of the fiber, some lignin was deposited as particles on the surface of the solid residues after hydrothermal treatment, and this part of the deposited lignin could not be solved by ethanol, the second step ethanol treatment changed the morphology of the deposited lignin, from granular lignin into a coating layer adsorbed on the surface of the fiber ,which resuled in low removal rate of lignin in hydrothermal-ethanol two-step treatment process.