基于LiCl/DMSO全溶体系麦草秸秆最佳球磨配球条件研究

Optimization of Balls-matching Method for Wheat Straw Ball Milling Based on LiCl/DMSO Solution

木质纤维全溶或组分分离过程中,需经一定程度球磨预处理以打破木质纤维原料细胞壁中各组分之间的联接,而球磨效率的高低与所选用球珠的直径大小和所占比例有密切关系。采用配球法对麦草秸秆进行球磨处理,分析球磨后麦草原料在LiCl/DMSO全溶体系中的溶解性能及其可抽提木质素得率,优选麦草最佳球磨条件。研究发现,当采用二级配球法时,麦草在LiCl/DMSO中的溶解性能较好,且对木质素化学结构影响较小,球磨效率较高;且随着球磨时间延长,麦草溶解性能增强,而可抽提木质素得率逐渐提高,即对木质素结构影响增强。综合考虑麦草溶解性能和木质素结构保护,选取二级配球法A_(110)B_9为麦草的最佳球磨方法。在此条件下,麦秆、麦鞘和麦叶的最佳球磨时间分别为6 h、6 h和4 h,且三级分的可抽提木质素得率分别为11.03%、10.44%和8.28%,均处于较低水平,说明该球磨条件下,木质素结构破坏程度很小,对后续木质素和木质素-碳水化合物复合体(LCC)组分的分离和结构保护具有重要意义。

In order to dissolve the lignocellulose or isolate some components, it is essential to take the ball milling step first to break the bonding between the components in the lignocellulose cell wall. The efficiency of the ball milling is close related to the size and proportion of the milling balls. Here groups of balls-matching methods were adopted to ball mill the wheat straw, and the optimum milling conditions were selected by detecting the dissolving performance in LiCl/DMSO solution of the ball milled wheat straw and its extractable lignin yield. It can be found that two-stage balls-matching method with two size of balls is better than the single-stage balls method with just one size balls for improving the dissolving performance and protecting the lignin structure of the wheat straw. And as the ball milling duration extending, the dissolving performance improved but the extractable lignin yield increased, which means the damage to the lignin structure also enhanced. Take into account both of the dissolving performance and protecting the lignin structure, the two-stage balls matching method A110B9 was selected as the best ball milling method for wheat straw. By this way, the optimum ball milling durations for wheat stalk, sheath and leaf fractions were 6 h, 6 h and 4 h, respectively. And the extractable lignin yields of these three fractions were 11.03%, 10.44% and 8.28%, separately. All these numbers are all at relatively lower stage, which also proved that the two-stage balls matching method A110B9 has very little damage to the lignin structure. It will be of great importance in the following for the lignin or lignin-carbohydrate complex isolation and protection.