<br>硫化纳米零价铁（S-nZVI）修复水体铬污染的过程和机制：实验和计算研究,Journal of Hazardous Materials

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硫化纳米零价铁（S-nZVI）修复水体铬污染的过程和机制：实验和计算研究
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2024-03-13 , DOI: 10.1016/j.jhazmat.2024.134031
Yuanyuan Wang ₁ , Yuesuo Yang ₂ , Jinyu Shi ₂ , Wengang An ₂ , Tao Lyu ₃ , Ping Zhang ₁

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硫化纳米级零价铁 (S-nZVI) 已成为一种先进的功能纳米材料，可有效修复水环境中的 Cr(VI) 污染。然而，对其相干过程、去除途径和水化学反应机制的了解还不够，这为其未来的环境应用带来了潜在的挑战。针对这一空白，本研究通过化学沉淀法成功合成了S-nZVI，并将其有效应用于Cr(VI)的去除。其他表征表明，Cr(VI) 的去除遵循一系列快速化学吸附和颗粒内扩散过程，同时伴随着 pH 值的升高和氧化还原电位的降低。修复机制包括协同将 Cr(VI) 还原为 Cr(III) 并通过 CrFeO 共沉淀同时固定。在填充有 S-nZVI 的砂柱中进行动态去除实验时，获得了最高的 Cr(VI) 去除能力 75 mg/g。进一步的计算分析，采用基于实验数据的密度泛函理论计算，揭示了 Cr(VI) 的多个分子轨道参与去除过程。它还阐明了以自由能降低为特征的 Cr(VI) 的逐步还原途径。这些发现为使用 S-nZVI 修复 Cr(VI) 提供了基于证据的见解，并且可以为未来重金属环境管理提供宝贵的技术支持。

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Processes and mechanisms in remediation of aqueous chromium contamination by sulfidated nano-scale zerovalent iron (S-nZVI): Experimental and computational investigations

Sulfidated nano-scale zerovalent iron (S-nZVI) has emerged as an advanced functional nanomaterial for efficiently remediating Cr(VI) contamination in aqueous environments. However, there is an insufficient understanding of its coherent process, removal pathway, and hydrochemical reactive mechanisms, presenting potential challenges for its future environmental applications. To address this gap, this study successfully synthesized S-nZVI through a chemical precipitation method and effectively applied it for the removal of Cr(VI). Additional characterization revealed that the removal of Cr(VI) followed a sequence of rapid chemisorption and intraparticle diffusion processes, concomitant with an increase in pH and a decrease in oxidation-reduction potential. The remediation mechanism encompassed a synergistic reduction of Cr(VI) to Cr(III) and simultaneous immobilization via CrFeO coprecipitation. The highest Cr(VI) removal capacity of 75 mg/g was attained during dynamic removal experiments in the sand column packed with S-nZVI. Further computational analysis, employing density functional theory calculations based on the experimental data, revealed the involvement of multiple molecular orbitals of Cr(VI) in the removal process. It also elucidated a step-by-step reduction pathway for Cr(VI) characterized by decreasing free energy. These findings provide evidence-based insights into Cr(VI) remediation using S-nZVI and can serve as valuable technical support for future environmental management of heavy metals.

更新日期：2024-03-13

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