Characterization of Ultrafiltration-Fractionated Humic Acid Derived from Chinese Weathered Coal by Spectroscopic Techniques

文献类型： 外文期刊

第一作者： Zhang, Shuiqin

作者： Zhang, Shuiqin;Yuan, Liang;Li, Yanting;Zhao, Bingqiang

作者机构：

关键词： Chinese weathered coal; ultrafiltration; humic acid fractions; aromatic structure; carboxyl group

期刊名称：AGRONOMY-BASEL （ 影响因子：3.417； 五年影响因子：3.64 ）

ISSN：

年卷期： 2021 年 11 卷 10 期

页码：

收录情况： SCI

摘要： Weathered coal is a widely used raw material of farm-oriented humic acid in China, while the high heterogeneity impedes its sufficient utilization. In this study, we fractionated the humic acid derived from Chinese weathered coal by ultrafiltration, and three fractions with the molecular range of & GE;100 kDa, 10-100 kDa, & LE;10 kDa were obtained. Subsequently, the chemical and spectral properties of the fractions were characterized by elemental analysis, potentiometric titration, Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and X-ray photoelectron (XPS) and other spectroscopy. The results showed that more than 60% of humic acid by weight was concentrated in the molecular range higher than 100 kDa, while only 3.25% was assigned to that with molecular weight lower than 10 kDa. The humic acid fraction with molecular weight higher than 100 kDa showed more carbon content, lower H/C atomic ratio, while higher E4/E6 ratio, more aromatic structure in FTIR, C-13 NMR, and XPS spectra, indicating a higher degree of aromaticity and stronger hydrophobicity. Conversely, there were more carboxyl groups and aliphatic structures, while fewer condensed aromatic rings for the humic acid fraction with molecular weight less than 100 kDa. These differences provide a baseline for the better utilization of weathered coal.

分类号：

  • 相关文献
作者其他论文 更多>>

微信小程序