红外光谱结合二维相关分析研究堆肥过程腐殖酸演化规律

Apply Fourier Transform Infrared Spectra Coupled with Two-Dimensional Correlation Analysis to Study the Evolution of Humic Acids During Composting

堆肥材料中腐殖酸的组成和结构直接影响堆肥产品品质和腐熟度。为研究堆肥腐殖酸的组成和形成过程,进行了生活垃圾堆肥并提取了不同堆肥阶段样品中的胡敏酸和富里酸,采用红外光谱和二维相关分析,探讨了堆肥过程胡敏酸、富里酸的组成、结构及随时间演化规律。红外光谱结果显示,堆肥胡敏酸组成复杂,在2 917~2 924,2 844~2 852,2 549,1 662,1 566,1 454,1 398,1 351,990~1 063,839,711cm-1均出现了吸收峰;相对于胡敏酸,堆肥富里酸结构简单,仅在1 725,1 637,990cm-1出现了吸收峰。上述吸收峰的出现表明堆肥胡敏酸和富里酸均含有木质素来源的苯环和糖类结构,但胡敏酸还含有丰富的脂族和蛋白类结构,这些在富里酸中含量较低;堆肥过程糖类、脂类、蛋白类及木质素结构均发生了降解,但是在胡敏酸和富里酸中它们的降解优先顺序不同。二维相关光谱分析结果表明,胡敏酸中降解先后顺序为脂肪类—蛋白类—多糖类和木质素,而富里酸中为蛋白质—多糖和脂肪类,降解过程均生成了羧酸、酮类和酯类结构,其中羧酸类物质一部分在堆肥中形成了碳酸盐。研究结果表明,红外光谱结合二维相关分析不仅可以获得堆肥腐殖酸官能团组成,还可以揭示堆肥过程这些官能团降解顺序,确定堆肥腐殖酸合成机制和动力学过程。

The composition and structure of humic acids formed during composting play an important influence on the quality and mature of compost.In order to explore the composition and evolution mechanism,municipal solid wastes were collected to com-post and humic and fulvic acids were obtained from these composted municipal solid wastes.Furthermore,fourier transform in-frared spectra and two-dimensional correlation analysis were applied to study the composition and transformation of humic and fulvic acids during composting.The results from fourier transform infrared spectra showed that,the composition of humic acids was complex,and several absorbance peaks were observed at 2 917~2 924,2 844~2 852,2 549,1 662,1 622,1 566,1 454, 1 398,1 351,990~1 063,839 and 711 cm-1 .Compared to humic acids,the composition of fulvci acids was simple,and only three peaks were detected at 1 725,1 637 and 990 cm-1 .The appearance of these peaks showed that both humic and fulvic acids comprised the benzene originated from lignin and the polysaccharide.In addition,humic acids comprised a large number of ali-phatic and protein which were hardly detected in fulvic acids.Aliphatic,polysaccharide,protein and lignin all were degraded during composting,however,the order of degradation was different between humic and fulvci acids.The result from two-dimen-sional correlation analysis showed that,organic compounds in humic acids were degraded in the following sequence：aliphatic＆gt;protein＆gt; polysaccharide and lignin,while that in fulvic acids was as following：protein＆gt; polysaccharide and aliphatic.A large number of carboxyl,alcohols and ethers were formed during the degradation process,and the carboxyl was transformed into car-bonates.It can be concluded that,fourier transform infrared spectra coupled with two-dimensional correlation analysis not only can analyze the function group composition of humic substances,but also can characterize effectively the degradation sequence of these groups and identified the formation mechanism and dynamics of humic substances during composting.