离子液处理过程中稻秸超微构造的变化

Ultrastructure of Rice Straw in the Process of Ionic Liquid Treatment

采用1-丁基-3-甲基咪唑氯盐([Bmim][Cl])和氯化胆碱―尿素离子液处理稻秸,探讨离子液用量、处理温度、处理时间对稻秸分离率和表面形貌的影响规律。结果显示,[Bmim][Cl]和氯化胆碱―尿素离子液均能分离稻秸。分离过程中,处理温度对分离效果的影响显著高于时间。在110℃,[Bmim][Cl]和氯化胆碱―尿素离子液对稻秸的分离率相当,在130℃,氯化胆碱―尿素对稻秸的分离率显著高于[Bmim][Cl]离子液。经离子液处理后,稻秸中木素纤维素被溶出,二氧化硅含量增加。通过扫描电子显微镜观察,[Bmim][Cl]和氯化胆碱―尿素离子液分离稻秸时,离子液首先攻击稻秸的内表面,然后逐渐渗入到稻秸内部,从内表面贯穿到外表面,内表面破坏的程度高于外表面。经离子液分离后稻秸外表层颗粒物形貌基本保持不变。

Rice straw was treated by 1-butyl-3-methylimidazolium chloride （[Bmim][Cl]） and choline chloride-urea ionic liquid respectively. The effects of content of ionic liquid, treated temperature, retention time on the efficiency of isolation and ultrastructure of rice straw were also investigated in this paper. Results showed that rice straw could be isolated by both of ionic liquids. The efficiency of isolation was significantly affected by treated temperature. The isolation ability of rice straw from choline chloride-urea was similar to [Bmim][Cl] ionic liquid at 110℃, while the isolation ability from choline chloride-urea was significantly higher than that from [Bmim][Cl] ionic liquid at 130℃. After treated by [Bmim][Cl] and choline chloride-urea ionic liquid, the content of silicon dioxide of rice straw was increased due to the isolation of lignincellulose. During isolation, ionic liquid firstly attacked the interior surface of rice straw, and then permeates, and crossed to the exterior surface. As a result, the decomposition of the interior surface was severer than the exterior surface. The granular zone was maintained in the outer surface of rice straw.