In this study, the effect of traditional acidification and hydrothermal acid hydrolysis on the separation of lignin and xylose from the pre-hydrolysis liquor (PHL) of kraft pulping process was comparatively evaluated. The PHL was acidified at room temperature or hydrothermally treated under acidic conditions to isolate lignin and xylose. As compared with the lignin removal rate of 26.8–32.7% by traditional acidification method, a much higher lignin removal rate of 57.1% was achieved by hydrothermal acid hydrolysis. Meanwhile, the content of xylose in the PHL increased dramatically from 7.91 to 13.91–34.82 g/L after the hydrothermal acid hydrolysis. The hydrophilicity of the obtained lignin gradually increased as evidenced by the decrease of the corresponding water contact angel. Additionally, the thermal stability of the lignin sample increased steadily with the increment of acid dosage. The hydrothermal acid hydrolysis provides an effective approach to fractionate lignin and xylose from PHL.

中文翻译：

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水热酸水解从牛皮纸制浆工艺预水解液中高效分离木质素和木糖

本研究对比评价了传统酸化和水热酸水解对牛皮纸制浆工艺预水解液（PHL）中木质素和木糖分离的效果。 PHL在室温下酸化或在酸性条件下水热处理以分离木质素和木糖。与传统酸化法26.8%~32.7%的木质素去除率相比，水热酸水解法的木质素去除率高达57.1%。同时，水热酸水解后PHL中木糖的含量从7.91急剧增加到13.91-34.82 g/L。所得木质素的亲水性逐渐增加，表现为相应的水接触角减小。此外，木质素样品的热稳定性随着酸用量的增加而稳定增加。水热酸水解提供了从 PHL 中分馏木质素和木糖的有效方法。