热处理竹材的化学成分傅里叶变换红外光谱分析

化学热处理是实现可再生木质生物能源中纤维素高效利用及半纤维素糖化转换的关键步骤。通过预处理过程可以快速去除难溶木质素，实现细胞壁中半纤维素的物理化分离，使得植物细胞壁中化学成分发生变化，从而增加木质纤维素的产出量。以硫酸(H₂SO₄)、稀碱(NaOH)及甘油(glycerol)为预处理介质，采用不同的热处理温度(硫酸(H₂SO₄)、稀碱(NaOH)热处理温度为117和135 ℃;甘油(glycerol)热处理温度为117 ℃))，对竹材处理前后的主要化学组分进行对比分析，并通过傅里叶变换红外光谱进一步证实化学热处理前后竹材化学组分的变化，以获得不同的化学热处理介入下竹材化学成分转换的主要变化规律和机理。结果表明：热化学处理后竹材的纤维素产出量明显增加。纤维素得率及木质素的去除率在不同的处理介质条件下的变化规律为，稀碱(NaOH)处理效果优于稀酸(H₂SO₄)和甘油(glycerol);此外，在相同介质条件下135 ℃热处理效果比117 ℃热处理效果显著。对于不同处理条件的半纤维素的降解程度大小变化结果与此相同。通过红外光谱分析可知，热处理后纤维素环状C-O-C不对称伸缩振动峰出现峰值分解，半纤维素的红外吸收特征峰出现明显陡降变化，木质素苯环特征吸收峰明显减弱，证明纤维素产出量明显增加，半纤维素降解趋势明显，木质素去除效果良好。傅里叶红外变换光谱分析结果与标准测定结果一致。

The Chemical Composition of Bamboo after Heat Pretreatment with Fourier Infrared Spectrum Analysis

Thermochemical pretreatment of lignocellulosic biomass is a critical step in obtaining high yields of cellulose and hemi-cellulose-derived sugars to realize effective utilization of cellulose in renewable biofuels.The pretreatment process can quickly re-move hard dissolving lignin and the physical separation of hemicelluloses in the cell wall while changing the chemical composition in plant cell wall,so as to increase the production of lignocellulose.Research with medium of sulfuric acid (H2 SO4 ),dilute alka-li (NaOH)and glycerin,and at different pretreatment temperature (117 and 135 ℃ in sulfuric acid (H2 SO4 )and dilute alkali (NaOH),117 ℃ in glycerin)analyzed and compared the main changes of chemical composition before and after the bamboo pro-cessing,and further confirmed that the mechanism of the chemical conversion after chemical pretreatment of bamboo through the Fourier infrared spectrum.The results showed that the output cellulose increased significantly after the thermochemical pretreat-ment.The change rules for yield of cellulose and the removal rate of lignin under the different pretreatment condition had been indicated dilute alkali (NaOH)treatment effect is better than that of dilute acid (H2 SO4 )and glycerin.In addition,the effect is more remarkable under the condition of 1 3 5 ℃ than 1 1 7 ℃ in the same medium.The changes of degradation degree of hemicellu-lose with different processing conditions were the same.The infrared spectrum analysis provided that C—O—C asymmetric stretching vibration peak appeared in cellulose decomposition after heat treatment,and it is the obvious steep fall in hemicellulo-ses infrared absorption characteristic peaks,benzene ring characteristic absorption peak of lignin has been abated.It is prove that yield of cellulose increased significantly,degradation trend of hemicelluloses is obviously,removal effect of lignin has also been better.The analysis results of Fourier infrared spectrum are consistent with the standard measurement.