Zhang Yuanqin, Li Yanhong, Chang Liping, Zi Changyu, Liang Guangbing, Zhang Dengfeng, Su Yi
Faculty of Chemical Engineering, Kunming University of Science and Technology Kunming 650500 People's Republic of China
Key Laboratory of Coal Science and Technology, Taiyuan University of Technology, Ministry of Education and Shanxi Province Taiyuan 030024 People's Republic of China.
RSC Adv. 2020 Jun 9;10(37):22002-22009. doi: 10.1039/d0ra03166f. eCollection 2020 Jun 8.
The lignite reserves of Zhaotong and Mile in China are abundant and lignite utilizations are limited, however, humic acids (HAs) extracted from lignites play a significant role in many fields including agriculture, environmental protection and so on. Herein, the structures of HAs extracted from Zhaotong and Mile lignites (denoted as ZLHA and MLHA, respectively) were characterized and compared to each other using comprehensive spectral analyses. As a result, the UV-Vis spectrum analyses of HAs indicated that the molecular weight of MLHA is larger than that of ZLHA. Cross polarization magic angle spinning C NMR, which is rarely used to analyze the structures of HAs using fitting peaks, and FT-IR spectrum analyses indicated that both the aromaticity and the oxygen-containing group contents of ZLHA are higher than those of MLHA, and the HAs' aromaticity could be confirmed by the results of the X-ray diffraction patterns. Additionally, the main existing forms of the elements in the HAs were obtained from X-ray photoelectron spectrum analyses, which are not commonly used for HA analyses. In this work, the utilization of comprehensive spectral analyses was an effective method to study the structural features of ZLHA and MLHA and it could provide a basic reference for the applications of ZLHA and MLHA.
中国昭通和弥勒的褐煤储量丰富，但褐煤利用率有限，然而，从褐煤中提取的腐殖酸（HAs）在农业、环境保护等诸多领域发挥着重要作用。在此，对从昭通褐煤和弥勒褐煤中提取的腐殖酸（分别记为ZLHA和MLHA）的结构进行了表征，并使用综合光谱分析进行了相互比较。结果表明，腐殖酸的紫外可见光谱分析表明MLHA的分子量大于ZLHA。交叉极化魔角旋转碳核磁共振（很少用于通过拟合峰分析腐殖酸结构）和傅里叶变换红外光谱分析表明，ZLHA的芳香性和含氧基团含量均高于MLHA，且腐殖酸的芳香性可通过X射线衍射图谱结果得到证实。此外，通过X射线光电子能谱分析获得了腐殖酸中元素的主要存在形式，该方法通常不用于腐殖酸分析。在这项工作中，综合光谱分析的应用是研究ZLHA和MLHA结构特征的有效方法，可为ZLHA和MLHA的应用提供基础参考。
