玉米芯水解残渣木质素的热解特性实验

Pyrolytic Characteristics of Lignin Derived from Corncob Hydrolysis Residues

摘要:

采用改进的酶解/温和酸解木质素(EMAL)法，从玉米芯水解残渣中提取出残渣木质素。借助热重分析仪对残渣木质素的热解过程进行了分析, 结果表明，残渣木质素的热裂解主要发生在200～500℃，在270℃和400℃出现2个明显的热解峰；残渣木质素在主要热解区间遵循二级反应模型。借助傅里叶红外变换仪对残渣木质素的主要官能团进行了研究，结果表明木质素的主要官能团在分离过程中未被破坏。残渣木质素及其热解焦炭的扫描电镜结果表明，木质素分子为多边形贝壳状结构，热解过程中发生了脆性和塑性变形，且随着热解终温的升高，热解焦表面形态趋于有序化。

Abstract:

Residual lignin was extracted from corncob hydrolysis residues using modified enzymatic mild acidolysis lignin (EMAL) method. The pyrolytic characteristics of the extracted lignin was investigated by thermal analyzer (TA), and its kinetic model was studied as well. It was shown that the pyrolysis of residual lignin mainly occurred at the temperature range of 200~500℃, with two loss peaks at 270℃ and 400℃ respectively. Kinetic study indicated that pyrolysis of residual lignin belongs to twoorder reaction. The main functional groups in residual lignin was characterized by fouriertransform infrared (FTIR) spectroscopy, which showed that main functional groups were not destructed during isolation. The surface morphology of residual lignin and its pyrolysis char was studied by scanning electronic microscopy (SEM). The analyses showed that the individual particles of lignin were polygonal in shape with multiple conchoidal fracture surfaces, which undergone brittle and plastic deformation during pyrolysis. When pyrolysis temperature increased, the char was more uniformed.