Yang Weilin, Xiang Wu, Bao Zhengyu, Huang Chunlei, Ma Ming, Lu Xinzhe, Yao Lingyang, Wang Yong
Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China.
Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China.
Environ Sci Pollut Res Int. 2022 Nov;29(51):77580-77592. doi: 10.1007/s11356-022-21303-w. Epub 2022 Jun 9.
This study was carried out to evaluate the contribution of different types of iron-organic matter associations (Fe-OM) to the phosphorus sorption capacity of peatland. Humic substance (HS) and particulate organic matter (POM) were isolated from peat soils, and different types of iron-organic matter associations (Fe-HS and Fe-POM) were prepared. Then, isothermal adsorption experiments were carried out on the synthesized Fe-OM and iron-contained peat soils. The morphology structure of Fe-HS associations is amorphous like that of ferrihydrite. The theoretical maximum adsorption capacity (Q) of Fe-HS associations can reach 36.90 mg/g, which is approximately two times higher than that of ferrihydrite (19.23 mg/g) and ten times higher than that of hematite (3.26 mg/g) and goethite (2.08 mg/g). Both peat soils and POM can strongly complex ferric ions, resulting in improved phosphorus sorption capacity. The Q of original peat soil and POM is 2.83 mg/g and 4.31 mg/g, which increased to 7.36 mg/g and 5.89 mg/g, respectively, after complexing ferric ions. Compared to inorganic Fe minerals, the associations of iron and organic matter (HS and POM) contribute more to the phosphorus retention ability of peat soils. However, the formation of Fe-OM associations could not fully explain why the addition of iron increases the phosphorus sorption capacity of peat soil by so much. Iron should also participate in other phosphorus retention processes, which need further exploration and research.
本研究旨在评估不同类型的铁-有机质结合体（Fe-OM）对泥炭地磷吸附能力的贡献。从泥炭土中分离出腐殖质（HS）和颗粒有机物（POM），并制备了不同类型的铁-有机质结合体（Fe-HS和Fe-POM）。然后，对合成的Fe-OM和含铁泥炭土进行了等温吸附实验。Fe-HS结合体的形态结构为无定形，类似于水铁矿。Fe-HS结合体的理论最大吸附量（Q）可达36.90mg/g，约为水铁矿（19.23mg/g）的两倍，赤铁矿（3.26mg/g）和针铁矿（2.08mg/g）的十倍。泥炭土和POM都能强烈络合铁离子，从而提高磷吸附能力。原始泥炭土和POM的Q分别为2.83mg/g和4.31mg/g，络合铁离子后分别增加到7.36mg/g和5.89mg/g。与无机铁矿物相比，铁与有机质（HS和POM）的结合体对泥炭土的磷保留能力贡献更大。然而，Fe-OM结合体的形成并不能完全解释为什么添加铁会使泥炭土的磷吸附能力提高这么多。铁还应参与其他磷保留过程，这需要进一步探索和研究。
