Hydrolysis of cellulose in dilute acid solution by NaOH/Urea freeze-melting pretreatment

doi:10.16085/j.issn.1000-6613.2017-1650

Abstract

Abstract: The hydrolysis of regenerated cellulose into glucose in diluted acid aqueous solution was studied by using NaOH/urea freeze-melting pretreatment system at -18℃. The morphological variation of cellulose pretreated with different ratio of NaOH/urea solution was analyzed by scanning electron microscopy(SEM)and X-ray diffraction(XRD). The results showed that the pretreated cellulose in the NaOH/urea system with a mass ratio of 7%:12% had the most rough surface and the best accessibility, In addition, the crystallinity of the cellulose was significantly decreased and the reactivity was greatly enhanced. A high glucose yield of 58.5% could be obtained at 180℃ in 4h reaction time in 0.025mol/L HCl aqueous solution, which was much higher than that obtained from the untreated cellulose (35.6%), indicating the excellent promoting effect of the pretreatment method on the cellulose hydrolysis. The developed method can be effectively applied to the treatment of the real agricultural wastes such as rice straw and corn stalk. The proposed process for the pretreatment and hydrolysis of cellulose had important scientific significance and application value for the high value utilization of lignocellulosic biomass.

Key words: cellulose, NaOH/urea freeze-melting, hydrolysis, glucose, biomass

摘要： 应用NaOH/尿素体系在-18℃下冻融预处理纤维素，探讨了不同实验条件对再生纤维素酸水解转化为葡萄糖效果的影响，同时分析了经过不同配比的NaOH/尿素体系处理后纤维素的形貌变化，并通过扫描电子显微镜（SEM）、X射线衍射（XRD）进行分析。实验证明在NaOH/尿素质量配比为7%∶12%的体系中，经过处理后的纤维素表面更加粗糙，纤维素的反应可及性大大增强，结晶度显著降低。在浓度为0.025mol/L的盐酸溶液中在180℃下反应4h，纤维素水解葡萄糖的产率可达到58.5%，而相同条件下的未处理纤维素水解葡萄糖产率为35.6%，可见预处理的优良效果。且该体系可以有效地应用于秸秆类农业废弃物的处理。所提出的纤维素预处理和水解体系对于木质纤维素的水解和高值资源化具有重要的科学意义和应用价值。

关键词: 纤维素, NaOH/尿素冻融, 水解, 葡萄糖, 生物质

CLC Number:

TQ35

XING Jingrun, SHEN Feng, QIU Mo, QI Xinhua. Hydrolysis of cellulose in dilute acid solution by NaOH/Urea freeze-melting pretreatment[J]. Chemical Industry and Engineering Progress, 2018, 37(06): 2159-2165.

邢静润, 申锋, 仇茉, 漆新华. NaOH/尿素冻融预处理纤维素及其酸催化水解[J]. 化工进展, 2018, 37(06): 2159-2165.

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