Stability of Organic Iron Complexes in Dajiuhu Peats and Its Ecological Significance

被引：0

作者：

Huang Y. ^{[1
]}

Zhao T. ^{[1
]}

Xiang W. ^{[1
,2
]}

Zhao Y. ^{[1
]}

Liu Y. ^{[1
]}

机构：

[1] School of Earth Sciences, China University of Geosciences, Wuhan

[2] Hubei Key Laboratory of Critical Zone Evolution, China University of Geosciences, Wuhan

来源：

Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | 2021年 / 46卷 / 05期

关键词：

Dissolved organic matter; Environmental geochemistry; Fluorescence quenching titration; Iron; Potentiometric titration; Stability constant;

D O I：

10.3799/dqkx.2020.149

中图分类号：

学科分类号：

摘要：

In order to study the complexing stability of organic iron complexes from peat, the stability of DOM-Fe2+, Fe3+ in different molecular weights of Dajiuhu peatland was determined by potentiometric titration and fluorescence quenching titration. There are obvious differences between the results of potentiometric titration (4.0-6.1) and fluorescence quenching titration (1.5-4.1), which can be explained by the deprotonation of OH in high pH value and the oxidation of Fe2+during the experiments. Potentiometric titration is suitable for studying the complexing stability of different molecular weights of DOM-Fe; the pH would not change during the experiment using fluorescence quenching titration method. Thus, the fluorescence method can be well applied to the element of variable valency. The results show that the complexing stability constants of DOM-Fe3+ is higher than that of Fe2+, and that of low-molecular-weight DOM with Fe2+ and Fe3+ is higher. The experiment indicates that high stability of DOM-Fe in peat, and relatively low-molecular-weight DOM has stronger ability to complex iron. Even Fe2+ is oxidized to Fe3+, it can still complex with DOM stably, which is conducive to the output of terrestrial dissolved iron to aquatic ecosystem. The complexing stability of iron organic complexes from peat will also affect the bioavailability of iron. © 2021, Editorial Department of Earth Science. All right reserved.

引用

页码：1862 / 1870

页数：8

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