Tuning Pb(II) Adsorption from Aqueous Solutions on Ultrathin Iron Oxychloride (FeOCl) Nanosheets.
Tuning Pb(II) Adsorption from Aqueous Solutions on Ultrathin Iron Oxychloride (FeOCl) Nanosheets.
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DOI：
10.1021/acs.est.8b07027
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发表时间：
2019-01
影响因子：
11.4
通讯作者：
Jinming Luo;Meng Sun;C. Ritt;Xia Liu;Yong Pei;J. Crittenden;M. Elimelech
中科院分区：
文献类型：
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作者：
Jinming Luo;Meng Sun;C. Ritt;Xia Liu;Yong Pei;J. Crittenden;M. Elimelech
层状二维 (2-D) 氯氧化铁 (FeOCl) 纳米片的结构可调性和表面功能对于获得卓越的吸附性能至关重要。在这项研究中，我们结合计算和实验工具来阐明 Pb(II) 在二维 FeOCl 纳米片上的独特吸附性质。在发现块状 FeOCl 片 (B-FeOCl) 具有良好的 Pb(II) 吸附特性后，我们应用计算量子力学模型来机械地探索代表性 FeOCl 面上的 Pb(II) 吸附。结果表明，增加 FeOCl 氧和氯位点的暴露量可显着增强 Pb(II) 的吸附。 FeOCl 的 (110) 和 (010) 面具有不同的氧和氯取向，导致不同的 Pb(II) 吸附能。因此，发现 (110) 面比 (010) 面对 Pb(II) 吸附更具选择性。为了利用这一见解，我们剥离了 B-FeOCl，以获得具有独特的富氯和富氧表面的超薄 FeOCl 纳米片 (U-FeOCl)。正如我们推测的，U-FeOCl 纳米片实现了优异的 Pb(II) 吸附能力（709 mg g-1 或 3.24 mmol g-1）。此外，U-FeOCl 表现出快速的吸附动力学，将吸附平衡时间缩短至 B-FeOCl 时间的三分之一。 FeOCl-Pb 吸附复合物的广泛表征证实了模拟结果，表明增加 Pb-O 和 Pb-Cl 相互作用位点的数量可以提高 U-FeOCl 的 Pb(II) 吸附能力。
Structural tunability and surface functionality of layered two-dimensional (2-D) iron oxychloride (FeOCl) nanosheets are critical for attaining exceptional adsorption properties. In this study, we combine computational and experimental tools to elucidate the distinct adsorption nature of Pb(II) on 2-D FeOCl nanosheets. After finding promising Pb(II) adsorption characteristics by bulk FeOCl sheets (B-FeOCl), we applied computational quantum mechanical modeling to mechanistically explore Pb(II) adsorption on representative FeOCl facets. Results indicate that increasing the exposure of FeOCl oxygen and chlorine sites significantly enhances Pb(II) adsorption. The (110) and (010) facets of FeOCl possess distinct orientations of oxygen and chlorine, resulting in different Pb(II) adsorption energies. Consequently, the (110) facet was found to be more selective toward Pb(II) adsorption than the (010) facet. To exploit this insight, we exfoliated B-FeOCl to obtain ultrathin FeOCl nanosheets (U-FeOCl) possessing unique chlorine- and oxygen-enriched surfaces. As we surmised, U-FeOCl nanosheets achieved excellent Pb(II) adsorption capacity (709 mg g-1 or 3.24 mmol g-1). Moreover, U-FeOCl demonstrated rapid adsorption kinetics, shortening adsorption equilibration time to one-third of the time for B-FeOCl. Extensive characterization of FeOCl-Pb adsorption complexes corroborated the simulation results, illustrating that increasing the number of Pb-O and Pb-Cl interaction sites led to the improved Pb(II) adsorption capacity of U-FeOCl.