不同物料堆肥富里酸的结构特征的研究

通过三维荧光平行因子分析（EEM-PARAFAC）和二维相关光谱（2DCOS）分析了富含木质纤维素类物料（果蔬废物和杂草废物）和富含木质素类物料（秸秆废物和园林修剪废物）堆肥形成的富里酸的结构和组成.结果显示，两类堆肥物料形成的富里酸结构差异显著.虽然两类物料的荧光组分含量及变化基本相似，但是特征官能团与其荧光组分的变化顺序却不同.富含木质纤维素类物料堆肥形成的富里酸中类酪氨酸和类色氨酸先于芳环形成，而富含木质素类物料堆肥形成的富里酸中芳环先于类酪氨酸和类色氨酸.并且，研究发现在堆肥高温期和腐熟期，富里酸的芳环含量在木质纤维类和木质类物料中分别增加了约10%和5%，脂肪族的含量分别下降了约10%和6%，说明堆肥过程中富里酸结构中脂肪族逐渐降解并伴随其芳香性逐渐增加；结构方程模型结果表明，类富里酸、脂肪族基团和羧基是富里酸中芳环形成的关键组分.本文研究结果可为明确堆肥过程中富里酸的形成提供理论基础.

Structural characteristics of fulvic acid composted with different materials

Fulvic acid (FA) is a major orgnaic component of composts. However, the heterogeneous structure of FA during the composting process of materials from different sources has not been fully studied. In this research, three-dimensional fluorescence parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation spectroscopy (2DCOS) were used to analyze the chemical structures of FA in lignocellulose-and lignin-rich composts, respectively. The results show that the order of change of characteristic functional groups is different, although with the similar chemical structure in FA from different composts. Tyrosine-like and tryptophan-like substance in FA from lignocellulose-rich composts are formed prior to aromatic rings. In addition, the aromatic rings precede tyrosine-like and tryptophan-like substance of FA formed by lignin-rich composts. Furthermore, the aromatic rings in FA increased by approximately 10% and 5%, and aliphatic group decreased by 10% and 6% in lignincellulose-and lignin-rich the thermophilic and mature stages, respectively. This result indicated that the degradation of aliphatic group might be accompanied by the aromatization of orgnic organic in FA during composting. Structural equation model showed that FA-like component, aliphatic groups and carboxyl groups are the key components affecting the formation of aromatic rings in FA. This study can provide a theoretical basis for clarifying the formation of FA by composting lignin-and lignocellulose-rich materials.