Chemical Industry and Engineering Progress ›› 2021, Vol. 40 ›› Issue (5): 2917-2927.DOI: 10.16085/j.issn.1000-6613.2020-1272

• Resources and environmental engineering • Previous Articles     Next Articles

Characteristics and influencing factors of environmental persistent free radicals of humic acid extracts from different types of soil

LU Yao1(), WANG Peng2(), YIN Mengnan1, YANG Mingyi1, ZHANG Huang3,4()   

  1. 1.Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China
    2.College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, Sichuan, China
    3.Faculty of Agriculture and Food, Kunming University of Science and Technology, Kunming 650500, Yunnan, China
    4.Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Kunming 650500, Yunnan, China
  • Received:2020-07-06 Online:2021-05-24 Published:2021-05-06
  • Contact: ZHANG Huang

不同类型土壤胡敏酸提取物环境持久性自由基特征及影响因素

鲁遥1(), 王朋2(), 尹梦楠1, 杨名毅1, 张凰3,4()   

  1. 1.昆明理工大学环境科学与工程学院,云南 昆明 650500
    2.成都理工大学生态环境学院,四川 成都 610059
    3.昆明理工大学农业与食品学院,云南 昆明 650500
    4.云南省土壤固碳与污染控制重点实验室,云南 昆明 650500
  • 通讯作者: 张凰
  • 作者简介:鲁遥(1995—),女,硕士研究生,研究方向为土壤中持久性自由基的稳定机制。E-mail:847119422@qq.com|王朋(1987—),男,工学博士,硕士生导师,研究方向为环境土壤科学。E-mail:wpeng0815@163.com
  • 基金资助:
    国家自然科学基金(41663014);云南省中青年学术和技术带头人后备人才项目(2018HB008);云南省万人计划青年拔尖人才项目

Abstract:

Environmentally persistent free radicals (EPFRs) are widespread in soil organic matter. There is still insufficient research about the relationship between its characteristics (signal strength, g-value and line width) and the structure of organic matter composition. In this study, humic acids (HAs) extracted from Heilongjiang black soil, Yunnan red soil and Shandong yellow soil were used as experimental samples. The signal characteristics of EPFRs in HAs were determined by electron paramagnetic resonance spectroscopy (EPR). Elemental analysis, ultraviolet spectrophotometry,13C NMR nuclear magnetic, high performance liquid phase and other methods were used to determine the structure, composition and molecular weight distribution of HAs. The results showed that the amount of EPFRs (0.84×1016—7.42×1016 spin/g) in HAs decreases with the increase of molecular weight. There were a significant positive correlation with the aromaticity of HAs (r=0.813, p<0.01), which is due to the fact that free electrons of aromatic compounds can partially separate domains to form EPFRs. The g values of EPFRs (2.0034—2.0041) decrease with the increase of aromaticity (r=-0.752, p<0.01). It was indicated that aromatic components have a major contribution to the carbon-centered free radicals. Compared with the soil in the other two regions, the EPFRs signal in Yunnan red soil with the rich Fe3+ content is the most stable. Under strong ultraviolet radiation in Yungui Plateau, it is more conducive to the formation of stable EPFRs. The present study is of great significance for understanding the environmental behavior of widely distributed EPFRs in soil.

Key words: natural organic matter, humic acid, molecular structure, environmental persistent free radical, aromaticity

摘要:

土壤有机质中存在环境持久性自由基(EPFRs),其特征(信号强度、g值和线宽)与天然有机质组分及其结构之间关联的研究还存在不足。本文采用黑龙江黑土、云南红土和山东黄土提取的胡敏酸(HAs)作为实验样品,通过电子顺磁共振波谱技术(EPR)分析测定HAs中自由基的信号特征,利用元素分析、紫外分光光度法、13C NMR核磁、高效液相等方法测定HAs提取物的结构、组分和分子量分布等。结果表明,HAs中EPFRs的 量(0.84×1016 ~7.42×1016 spin/g)随着分子量的增加而减少,且与HAs的芳香性有显著的正相关关系(r=0.813, p<0.01),这归因于芳香族化合物自由电子能够部分离域形成EPFRs。EPFRs的g值(2.0034~2.0041)随芳香性的增加而减少(r=-0.752,p<0.01),表明芳香性组分对碳中心自由基有主要的贡献。相比于其他两个地区的土壤,红土HAs中EPFRs信号最稳定,主要归因于云南土壤中Fe3+含量丰富,在强紫外线的辐射下更有利于形成稳定的EPFRs。

关键词: 天然有机质, 胡敏酸, 分子结构, 环境持久性自由基, 芳香性

CLC Number: 

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