The complex interlacing structure among cellulose, hemicellulose and lignin and the unique properties of lignin itself limit the value-added utilization of the lignin. As the “upstream” process of biorefinery, lignin separation technology is very important for lignin conversion into high-value materials. However, it is not easy to extract lignin with relatively complete structure without affecting performance from biomass raw materials. Notably, most of reviews regarding lignin focus on its degradation. The extraction or separation methods are not introduced in detail, and the effects of these methods on raw materials or lignin have not been reported. Herein, this paper critically reviews the changes in physicochemical properties and structure of lignin caused by several mild organic solvent extraction methods and new ionic liquids which has been widely used in recent years. Furthermore, the application and potential economic benefits of these lignin are summarized. These methods promote the effective utilization of lignin, which is no longer limited to heat energy, but also alleviates the solid waste disposal problem caused by lignin as waste stream. Finally, perspectives on the future research on the lignin separation, depolymerization and application are highlighted. This review may provide an insight for the development of bio-refining technology.

纤维素，半纤维素和木质素之间复杂的交错结构以及木质素本身的独特性质限制了木质素的增值利用。作为生物精炼的“上游”过程，木质素分离技术对于将木质素转化为高价值材料非常重要。但是，要提取具有相对完整结构的木质素而不影响生物质原料的性能并不容易。值得注意的是，有关木质素的大多数评论都集中在其降解上。没有详细介绍提取或分离方法，也没有报道这些方法对原料或木质素的影响。在这里 本文对近年来几种广泛应用的温和有机溶剂萃取方法和新型离子液体对木质素理化性质和结构的变化进行了综述。此外，总结了这些木质素的应用和潜在的经济利益。这些方法促进了木质素的有效利用，不再局限于热能，而且减轻了木质素作为废物流引起的固体废物处理问题。最后，重点介绍了木质素分离，解聚和应用的未来研究前景。该评论可能为生物精炼技术的发展提供见解。这些方法促进了木质素的有效利用，不再局限于热能，而且减轻了木质素作为废物流引起的固体废物处理问题。最后，重点介绍了木质素分离，解聚和应用的未来研究前景。该评论可能为生物精炼技术的发展提供见解。这些方法促进了木质素的有效利用，不再局限于热能，而且减轻了木质素作为废物流引起的固体废物处理问题。最后，重点介绍了木质素分离，解聚和应用的未来研究前景。该评论可能为生物精炼技术的发展提供见解。