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war3one金虫 (著名写手)
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[求助]
生物质红外图谱分析汉译英
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FTIR 可以分析处理前后组分中不同官能团位置的变化，而官能团吸收峰位置和相对强度的变化能够反映秸秆半纤维素，木质素和纤维素组分的变化，特别是木质素组分的变化能够有效的影响纤维素的酶解糖产率为了验证上述的结构的改变，因此为了验证上述秸秆中结构的变化，对原始物料与预处理后物料进行FTIR分析(图3). 其中3399 cm-1 和2919 cm-1 为特征吸收峰，代表C-H伸缩振动和-OH 官能团，这些谱峰的存在归因于物料中纤维素，半纤维素和木质素的存在，表明了处理前后物料组分构成并无明显的变化。1240 cm-1特征吸收峰的透光强度变化反映了半纤维素与木质素相互作用的酯键，可以看到，经NaOH处理后透光强度减弱，表明一部分木质素被移除；而再次经过酸预处理后，吸收峰的透光强度有微量的增强，可能的原因是原料变的多孔和多条结构，使原料内部的共价键能够充分暴露。而1104 cm-1反映了纤维素与半纤维素间共价键的特征吸收峰，第一次预处理后其透光强度有明显增大，这是由于原料在去除一定的木质素和半纤维素后，使得比表面积增加，原本被结晶纤维素包裹的纤维素与半纤维素结合区域更多的暴露出来，而通过第二次预处理，更多的半纤维素被去除，反应在红外图谱上为透光强度又有所减弱，这些结论与上述结果是一致的。 1630 cm-1特征吸收峰（~C-O）反映了木质素组分的变化，经过第一次预处理，1630的特征吸收峰明显降低，而经过第二次预处理后吸收峰又有增强，但是小于未处理的物料，这种结果与上述结果符合。 |
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andrewzhang
铁杆木虫 (著名写手)
超级无敌加菲
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war3one: 金币+120, 翻译EPI+1, ★★★★★最佳答案 2013-08-04 09:55:27
war3one: 金币+120, 翻译EPI+1, ★★★★★最佳答案 2013-08-04 09:55:27
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The changes of position for the functional groups could be analysed by the FTIR, and their positions and intensities could be considered as a reflection of changes in hemicellulose, cellulose and lignin, especially when the variation of lignin could effect the yield of saccharides for enzymatic hydrolysis of cellulose. Thus, in order to verify the change of compositions in straws, the raw material and the product after treatment were analysed by FTIR (Fig. 3). |
2楼2013-08-01 21:13:36
andrewzhang
铁杆木虫 (著名写手)
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The characteristic absorption peaks at 3399 cm-1 and 2919 cm-1 correspond to the vibration of C-H and funtional group -OH, respectively. Their existence indicated the existence of cellulose, hemicellulose and lignin, in other words, there was not a significant change in structure before and after the treatment. The absorption peak at 1240 cm-1 stands for the ester bond in the hemicellulose and lignin interaction. A diminution of transparency could be told before and after the treatment of NaOH, which indicated that partial of lignin was removed by the very step. However, the slightly increase of transparency after pre-treatment of acid, could be brought by the porous and multiple-rod structure cased by the treatment, which could cause a secondary exposure of covalent bonds. Moreover, the pick at 1104 cm-1, who was exactly the absorption peak of covalent bond between cellulose and hemicellulose, have experienced a evident increase of transparency after the 1st pre-treatment (corresponded to the increase of surface and exposure of covalent bonds), and diminution after the 2nd pre-treatment (corresponded to the removal of hemicellulose). The variation of this peak correspond well the statements before. The peak at 1630 cm-1 (indicates -C-O-) reflected the variation of lignin. After the 1st pre-treatment, it suffered a significant decrease, then a increase after 2nd pre-treatment (but still less than that of raw materials), which made a nearly perfect correspondence to the results stated before. |
3楼2013-08-01 21:38:46