土壤有机质级份的红外和热重特性

CHRACTERISTICS OF SOIL HUMIC SUBSTANCES BY INFRARED SPECTRA AND THERMAL GRAVITY

用红外分析(FTIR)和热失重分析法对从三种不同利用方式下的黄泥土中提取出的FA,HA及用酸性二甲基亚砜(DMSO)和HF HCl两种方法提取胡敏素的元素组成及结构特征进行分析,结果表明:胡敏素占腐殖质总碳的60—70%,FA和HA分别占10%和15%左右;不同利用方式下土壤的DMSO humin,HF humin1,HF humin2在波数2930/1640处的吸收强度比分别为1.18—1.44,0.32—0.43,0.37—0.41;DMSO humin在78—86℃和264—282℃出现了主要的失重峰,HF humin1和HF humin2的主要失重峰在333—338℃和438—458℃之间,FA和HA的主要失重峰分别在300℃和359℃左右,说明用DMSO提取的胡敏素脂肪族类物质较多,缩合程度较低;而用HF HCl提取的则含较多的芳香族类物质,缩合程度较高.

Humin from different use types in yellow earth was prepared by the HF/HCl treatment method as well as by the DMSO extraction method .Humin, FA and HA were measured by using thermal gravity analysis and FTIR spectrum .The results showed that humin, FA and HA carbon account for 60—70%, 10%, 15% of the total carbon of humic substance ,respectively. DMSO-extraction was characterized by a lower degree of unsaturation compared with HF-humin. The main peak of weight loss of DMSO-humin were 78—86℃和264—282℃,however the HF-humin were 333—338℃ and 438—458℃,and FA was 300℃,HA was 359℃.This indicated that DMSO-humin contained a larger amount of aliphatic components, while HF—humin may have more aromatic constituents.