Purification is an important approach to improve the added value utilization of xylo-oligosaccharides with 2–4 degree of polymerization (XOS_{DP 2–4}) in pre-hydrolysis liquor (PHL). In order to improve the purification efficiency of PHL, rotary evaporation was explored to promote the inhibitor removal in poplar PHL. Influence of rotary evaporation on the composition and properties of PHL were investigated. After evaporation-Ca(OH)₂-AC purification, the xylo-oligosaccharide in the purified PHL could be used to prepare XOS_DP2−4 by enzymolysis of xylanase. The results showed that there was no loss of the total xylose/xylo-oligosaccharides during the rotary evaporation process, and evaporation also promoted the removal of lignin from PHL during the subsequent Ca(OH)₂ and activated carbon (AC) treatment process, and the lignin removal increased from 57.80 % to 71.91 %. Furthermore, the furfural and acetic acids in PHL were separated and removed by condensation with the yields of 90.84 % and 23.63 %, respectively. 63.75 % of the XOS_{DP 2–4} yield was obtained after rotary evaporation-Ca(OH)₂-AC purification and enzymolysis of xylanase based on the total xylose/xylo-oligosaccharides of the purified PHL with an increase of 25.12 % compared to the Ca(OH)₂-AC purified PHL.

纯化是提高预水解液 (PHL) 中_2-4聚合度 (XOS _{DP 2-4} )低聚木糖的附加值利用率的重要途径。为了提高PHL的纯化效率，探索了旋转蒸发促进杨树PHL中抑制剂的去除。研究了旋转蒸发对PHL组成和性质的影响。蒸发-Ca(OH) ₂ -AC纯化后，纯化后的PHL中的低聚木糖可用于制备XOS _DP2-4通过木聚糖酶的酶解。结果表明，在旋转蒸发过程中木糖/低聚木糖总量没有损失，并且在随后的Ca(OH) ₂和活性炭(AC)处理过程中，蒸发也促进了PHL中木质素的去除，并且木质素去除率从 57.80 % 增加到 71.91 %。此外，PHL中的糠醛和乙酸通过缩合分离和去除，产率分别为90.84%和23.63%。在旋转蒸发-Ca(OH) ₂ -AC 纯化和木聚糖酶酶解后获得63.75% 的 XOS _{DP 2-4}产率，基于纯化的 PHL 的总木糖/低聚木糖，与之前相比增加了 25.12% Ca(OH) ₂-AC纯化的PHL。