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AlCl3促进毛竹低共熔体系预处理效率的研究

AlCl3Incorporation Facilitated the Deep Eutectic Solvent Pretreatment

  • 摘要: 研究了一种AlCl3辅助的低共熔溶剂(DES)预处理毛竹的方法。合成了以氯化胆碱和AlCl3为氢受体,愈创木酚为氢供体的低共熔溶剂,考察了低共熔溶剂中AlCl3用量对毛竹原料的化学组成、物料得率和后续酶水解效率的影响,结果表明:随着AlCl3用量的增加,预处理物料木聚糖和木质素含量逐渐降低,葡聚糖含量升高,葡聚糖酶水解得率显著提高。当AlCl3用量为1.32%(摩尔分数),氯化胆碱、愈创木酚和AlCl3物质的量比为25∶50∶1)时,预处理效果达到最佳,预处理物料得率为57.16%,葡聚糖和木聚糖回收率分别为95.95%和12.84%,木质素脱除率为74.88%,葡聚糖酶水解得率由未添加AlCl3时的11.16%提高到96.20%,表明AlCl3可以有效促进DES体系对毛竹中木聚糖和木质素的溶解。通过XRD、SEM和FT-IR分析对预处理后物料进行表征。XRD分析结果表明预处理物料的结晶度随着AlCl3用量的增加逐渐增加,主要是由于木质素和木聚糖组分逐渐被脱除,而纤维素组分无明显破坏;SEM分析结果发现预处理后物料纤维出现碎片化和团聚现象,随着AlCl3用量的增加原料组分被逐渐溶解和破坏;FT-IR分析结果也进一步证明,预处理后的物料中纤维素含量的增加,伴随着木聚糖和木质素含量逐渐减少。

     

    Abstract: The paper presented a method for the pretreatment of bamboo wood with AlCl3 assisted eutectic solvent(DES). The DES was synthesized using choline chloride and AlCl3 as the hydrogen acceptors, and guaiacol used as the hydrogen donors. The effects of AlCl3 dosage in DES on the chemical composition and subsequent enzymatic hydrolysis efficiency of the pretreated bamboo were investigated. The results showed that with the increase of AlCl3 dosage, the contents of xylan and lignin decreased gradually with the content of glucan increased in pretreated bamboo, which significantly improved its enzymatic hydrolysis efficiency. Under optimal conditions(the amount of choline chloride, guaiacol and AlCl3 was 25∶50∶1). The conversion rate was 42.84%, the recovery of glucan and xylan were 95.95% and 12.84%, respectively, with 74.88% lignin removal. Compared with the DES treatment without the addition of AlCl3, glucan enzymatic hydrolysis with AlCl3-assisted DES treatment increased from 11.16% to 96.20%. The results demonstrated that AlCl3 could effectively promote the dissolution of xylan and lignin. The pretreated materials were characterized by XRD, SEM, and FT-IR. XRD analysis showed that with the increase of AlCl3 dosage, the crystallinity of the pretreated materials increased gradually, mainly due to the gradual removal of lignin and xylan components, while the cellulose components were not significantly damaged. SEM analysis showed that after pretreatment, the pretreated materials appeared obviously fragmentation and agglomeration. With the increase of AlCl3 dosage, the bamboo components were gradually dissolved and destroyed. The FT-IR analysis results also proved that the increase of cellulose content in the pretreated materials accompanied by the gradual decrease of xylan and lignin.

     

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