乙醇沉淀法提取木质纤维预水解液中半纤维素研究

2019 年 6 月 Journal of Chemical Engineering of Chinese Universities June 2019 文章编号：1003-9015(2019)03-0636-09

乙醇沉淀法提取木质纤维预水解液中半纤维素研究

王雷明1, 石海强1,2, 王鑫1, 周妙方1, 李娜1, 牛梅红1

(1. 大连工业大学轻工与化学工程学院，辽宁大连 116034;

2. 华南理工大学制浆造纸工程国家重点实验室, 广东广州 510640)

摘要：硫酸盐法溶解浆生产时，预水解液(PHL)中含有大量半纤维素，将其分离可用于多种高附加值产品的制备。

针对乙醇法回收半纤维素得率以及纯度较低的问题，优化了乙醇沉降半纤维素预水解条件以及乙醇-预水解液(ET-PHL)

的体积比，通过浓缩、酸化、聚氧化乙烯絮凝处理及碱化处理显著地提高了半纤维素产品的得率。结果显示，在ET-PHL

体积比为10、P因子为200时，最有利于半纤维素分离，得率及纯度为3.43 g⋅L-1和69.57%。进一步实验结果表明在

浓缩90%后得率及纯度为6.11 g⋅L-1和71.38%，酸化至pH值为2再经400 mg⋅L-1聚氧化乙烯絮凝处理两步去除木质

素后得率为4.98 g⋅L-1，但纯度提高到了82%，而再碱化至pH值为6时，得率提高到了9.87 g⋅L-1但纯度下降到了76.47%，进一步提高pH，虽然沉淀得率继续有所提升，但灰分含量会显著上升。

关键词：预水解；半纤维素；酸化；絮凝处理；碱化

中图分类号：TQ353.9；TS79 文献标志码：A DOI：10.3969/j.issn.1003-9015.2019.03.017

Extraction of hemicellulose from pre-hydrolysis liquor of lignocellulose

by ethanol precipitation

WANG Lei-ming1, SHI Hai-qiang1,2, WANG Xin1, ZHOU Miao-fang 1, LI Na1, NIU Mei-hong1

(1. School of Light Industry & Chemical Engineering, Dalian Polytechnic University, Dalian 116034, China;

2. State Key Laboratory of Pulp and Paper Engineering, South China University of Technology,

Guangzhou 510640, China)

Abstract: Pre-hydrolysis liquor contains large amount of hemicellulose in dissolving pulp production via kraft-based processes. These hemicelluloses can be isolated, purified and converted into many high value-added products. The yield and purity of hemicellulose recovered by ethanol are usually low. In this study, the pre-hydrolysis conditions of acacia wood and volume ratio of ET-PHL(ethanol—pre-hydrolysis liquor) were optimized for higher yield of hemicellulos recovery by ethanol precipitation. Hemicellulose yield was greatly improved after concentration, acidification, polyethylene oxide flocculation and alkali treatments. The results show that the best separation performance happens when the volume ratio of ET-PHL is 10 and the P factor is 200, and the yield and purity are 3.43 g⋅L-1 and 69.57 %, respectively. Further experimental results show that the yield and purity are 6.11 g⋅L-1 and 71.38 % after concentrating by 90 %. After adjusting to pH 2 and with polyethylene oxide flocculation treatment (400 mg⋅L-1), the yield is reduced to 4.98 g⋅L-1 but the purity is increased to 82 %. When adjusted to pH 6, the yield is increased to 9.87 g⋅L-1 but the purity decreases to 76.47 %. Further increase of pH can keep improving the yield, but the ash content increases significantly.

Key words: pre-hydrolysis; hemicellulose; acidification; flocculation; alkalization

1前言

半纤维素广泛存在于高等植物的细胞壁中[1]，在自然界中的储量丰富。作为一种非均一性多糖，半

收稿日期：2018-08-08；修订日期：2018-11-04。

基金项目：国家自然科学基金项目(31470603)；国家重点实验室项目(201746)。