机械洞察力Cr(VI) 通过含Si的化的保留
Ying Hu1, Qiang Xue1, Honghan Chen1
1MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China.
Journal of environmental sciences (China)
|December 17, 2023
概括
六价 (Cr(VI)) 对酸铁 (Si-Fh) 的吸附随着Si/Fe比率的增加而减少. 这是由于更大的静电排斥,超过了增强的复杂化,影响了土壤和含水层中Cr (VI) 的去除.
科学领域:
- 环境科学 环境科学
- 地质化学 地质化学
- 材料科学 材料科学 材料科学
背景情况:
- 六价 (Cr(VI)) 由于其毒性,可溶性和可移动性,造成了重大环境风险.
- 铁 (Fh) 是土壤和含水层中Cr (VI) 的关键吸附剂,经常与酸盐 (Si) 共存,形成Si-Fh混合物.
- 在Si-Fh混合物中的Cr (VI) 保留机制仍然不太清楚.
研究的目的:
- 研究Cr(VI) 对Si-Fh的吸附行为和机制,具有不同的Si/Fe摩尔比率.
- 阐明在Si-Fh上Cr(VI) 吸附中静电相互作用和复杂化之间的相互作用.
- 提供有关Si-Fh.含有Si-Fh.的环境中的Cr(VI) 命运和运输的见解.
主要方法:
- 使用传输电子显微镜 (TEM),里叶变换红外光谱 (FTIR),X射线衍射 (XRD) 和X射线光电子光谱 (XPS) 等技术,对Si-Fh和Cr(VI) 负载Si-Fh进行表征.
- 在不同Si/Fe比率下进行吸附实验以量化Cr (VI) 的吸收.
- 密度函数理论 (DFT) 计算以支持对吸附机制的实验发现.
主要成果:
- 随着Si/Fe比率的上升,Si-Fh的特定表面积增加,但Cr的吸附能力下降.
- 增加Si/Fe比率导致零电荷点较低,增强Si-Fh和CrVI之间的静电排斥.
- 由于吸附基 (A-OH-) 的增加,观察到增强的复杂化,但其影响力不如静电排斥.
结论:
- 静电排斥在控制Si-Fh上的Cr (VI) 吸附方面发挥着主导作用,在较高的Si/Fe比率下取代了增加复杂化的效应.
- DFT的计算证实了电子变异和反应能量增加,Si/Fe比率更高,支持实验观测.
- 了解这些机制对于预测和减轻相关环境系统中Cr6污染至关重要.
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