Fe(II)-Catalyzed Transformation of Ferrihydrite with Different Degrees of Crystallinity.
Fe(II)-Catalyzed Transformation of Ferrihydrite with Different Degrees of Crystallinity.
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DOI：
10.1021/acs.est.3c00555
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发表时间：
2023-04
影响因子：
11.4
通讯作者：
Yuyan Liu;Yuefei Ding;Anxu Sheng;Xiaoxu Li;Jiawei Chen;Y. Arai;Juan Liu
中科院分区：
文献类型：
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作者：
Yuyan Liu;Yuefei Ding;Anxu Sheng;Xiaoxu Li;Jiawei Chen;Y. Arai;Juan Liu
天然存在的水铁矿（Fh）纳米粒子具有不同程度的结晶度，但Fh结晶度如何影响其转化行为仍然是难以捉摸的。在这里，我们研究了具有不同结晶度的Fh的Fe（II）催化转化（即，Fh-2h、Fh-12h和Fh-85C）。Fh-2 h、Fh-12 h和Fh-85 C的X射线衍射图分别显示2个、5个和6个衍射峰，表明结晶度顺序为：Fh-2 h < Fh-12 h < Fh-85 C。低结晶度的Fh具有较高的氧化还原电位，对应于Fe（II）-Fh界面电子转移较快和Fe（III）不稳定生成。随着Fe（II）初始浓度（[Fe（II）aq] int.）在0.2 ~ 5.0mM范围内，Fh-2 h和Fh-12 h的转化途径由Fh →纤铁矿（Lp）→针铁矿（Gt）转变为Fh → Gt，而Fh-85 C的转化途径由Fh → Gt转变为Fh →磁铁矿（Mt）。合理化的变化，使用一个计算模型，定量描述的自由能之间的关系，开始Fh和成核障碍的竞争产品相的形成。Fh-2 h转化的Gt颗粒比Fh-12 h和Fh-85 C转化的Gt颗粒具有更宽的宽度分布。在[Fe（II）aq]int.= 0.00000时，由Fh-85 C转变形成了不常见的六方Mt纳米片。5.0这些发现对于全面了解Fh和其他相关元素的环境行为至关重要。
Natural occurring ferrihydrite (Fh) nanoparticles have varying degrees of crystallinity, but how Fh crystallinity affects its transformation behavior remains elusive. Here, we investigated the Fe(II)-catalyzed transformation of Fh with different degrees of crystallinity (i.e., Fh-2h, Fh-12h, and Fh-85C). X-ray diffraction patterns of Fh-2h, Fh-12h, and Fh-85C exhibited two, five, and six diffraction peaks, respectively, indicating the order of crystallinity: Fh-2h < Fh-12h < Fh-85C. Fh with the lower crystallinity has a higher redox potential, corresponding to the faster Fe(II)-Fh interfacial electron transfer and Fe(III)labile production. With the increase of initial Fe(II) concentration ([Fe(II)aq]int.) from 0.2 to 5.0 mM, the transformation pathways of Fh-2h and Fh-12h change from Fh → lepidocrocite (Lp) → goethite (Gt) to Fh → Gt, but that of Fh-85C switches from Fh → Gt to Fh → magnetite (Mt). The changes are rationalized using a computational model that quantitatively describes the relationship between the free energies of formation for starting Fh and nucleation barriers of competing product phases. Gt particles from the Fh-2h transformation exhibit a broader width distribution than those from Fh-12h and Fh-85C. Uncommon hexagonal Mt nanoplates are formed from the Fh-85C transformation at [Fe(II)aq]int.= 5.0 mM. The findings are crucial to comprehensively understand the environmental behavior of Fh and other associated elements.