不同预处理对秸秆木质纤维组分特性的影响

Effects of Different Pretreatments on Fiber Component Characteristics of Corn Straw

为研究沼液、组合碱和白腐菌3种不同预处理方式对玉米秸秆纤维组分(纤维素、半纤维素和木质素)含量及晶体结构的影响,分别将沼液与玉米秸秆按5∶2的比例混合预处理5d,组合碱(氢氧化钠和氢氧化钙质量比是2∶1)按1∶5的固液比例添加预处理5d,白腐菌按5%比例添加预处理10d。采用范式(Van Soest)纤维测定法、傅里叶变化红外光谱(FTIR)和X射线衍射(XRD)对预处理前后的玉米秸秆纤维结构变化进行研究。结果表明:经3种方式预处理后玉米秸秆的纤维组分含量均降低,其中组合碱预处理后玉米秸秆木质素结构的破坏程度比沼液和白腐菌预处理更加显著,有利于促进纤维素的转化,木质素含量分别下降7.73%、16.79%和6.92%;不同预处理后玉米秸秆纤维素的结晶结构均出现不同程度破坏,结晶度分别下降9.3%、12.4%和10.9%,其中组合碱预处理的结晶度下降最大,更加有利于增加纤维素酶的可及度,提高纤维素的水解效率;FTIR的分析结果表明,组合碱预处理对玉米秸秆纤维组分的结构破坏程度最大。本研究可为更高效、合理调控秸秆沼气工程预处理提供理论基础。

In order to study the ef fects of 3 kinds of di fferent pret reatment materials （biogas slurry, combined alkal i and whi te rot fungi） on the contents and crystal structures of corn straw fiber components （cel lulose, hemicel lulose and lignin）, the biogas slurry and corn straw were mixed by 5：2 ratio for 5d pretreatment, combined alkali （sodium hydroxide and calcium hydroxide mass ratio of 2：1） were added by the solid-liquid ratio of 1：5 for 5d pretreatment, and the proportion of 5% white rot fungus was used for the pretreatment in 10d. The structure characteristics of straw fiber before and after pretreatments were measured by using Soest （Van） fiber measurement, Fourier transform infrared spectroscopy （FTIR） and X ray diffraction （XRD）. The results showed that the corn straw fiber contents decreased after each of the 3 kinds of pretreatment, the destruction degree of lignin structure of corn straw was more significant than that of biogas slurry and white rot fungus pretreatment, and the transformation of cel lulose, the lignin contents were decreased by 7.73%, 16.79% and 6.92%, respectively. After different pretreatments, the crystalline structures of cel lulose in corn straw were damaged to a certain degree, and crystallinity decreased by 9.3% , 12.4% and 10.9% , respectively, the cel lulose crystallinity of corn straw decreased the most under combined alkali pretreatment, which was beneficial to increase the accessibility of cel lulase and improve the hydrolysis efficiency of cel lulose. The result of FTIR showed that there had the greatest damage to the structure of corn straw fiber components under combined alkali pretreatment methods. Thus, this research could provide a theoretical basis for more efficient and reasonable regulating pretreatment of straw biogas project.