Stability of Fe-As composites formed with As(V) and aged ferrihydrite

文献类型： 外文期刊

第一作者： Yang, Zhonglan

作者： Yang, Zhonglan;Sun, Benhua;Yang, Zhonglan;Bai, Lingyu;Su, Shiming;Wang, Yanan;Wu, Cuixia;Zeng, Xibai

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关键词： Fe-As composites; Transformation products; Sorption ability; Crystallization; Aged

期刊名称：JOURNAL OF ENVIRONMENTAL SCIENCES （ 影响因子：5.565； 五年影响因子：5.066 ）

ISSN： 1001-0742

年卷期： 2021 年 100 卷

页码：

收录情况： SCI

摘要： During the aging process, ferrihydrite was transformed into mineral mixtures composed of different proportions of ferrihydrite, goethite, lepidocrocite and hematite. Such a transformation may affect the fixed ability of arsenic. In this study, the stability of Fe -As composites formed with As(V) and the minerals aged for 0, 1, 4, 10 and 30 days of ferrihydrite were systematically examined, and the effects of molar of ratios Fe/As were also clarified using kinetic methods combined with multiple spectroscopic techniques. The results indicated that As(V) was rapidly adsorbed on minerals during the initial polymerization process, which delayed both the ferrihydrite conversion and the hematite formation. When the Fe/As molar ratio was 1.875 and 5.66, the As(V) adsorbed by ferrihydrite began to release after 6 hr and 12 hr, respectively. The corresponding release amounts of As(V) were 0.55 g/L and 0.07 g/L, and the adsorption rates were 92.43% and 97.50% at 60 days, respectively. However, the As(V) adsorbed by the transformation products aged for 30 days of ferrihydrite began to release after adsorbed 30 days. The corresponding release amounts of As(V) were 0.25 g/L and 0.03 g/L, and the adsorption rates were 84.23% and 92.18% after adsorbed 60 days, for the Fe/As=1.875 and 5.66, respectively. Overall, the combination of As(V) with ferrihydrite and aged products transformed from a thermodynamically metastable phase to a dynamically stable state within a certain duration. Moreover, the aging process of ferrihydrite reduced the sorption ability of arsenate by iron (hydr)oxide but enhanced the stability of the Fe -As composites. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

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