Sulfidation of Nanoscale Zero-Valent Iron by Sulfide: The Dynamic Process, Mechanism, and Role of Ferrous Iron,Environmental Science & Technology

当前位置： X-MOL 学术 › Environ. Sci. Technol. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Sulfidation of Nanoscale Zero-Valent Iron by Sulfide: The Dynamic Process, Mechanism, and Role of Ferrous Iron
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2024-09-12 , DOI: 10.1021/acs.est.4c04390
Wenqiang Xu ₁ , Chenyun Xia ₁ , Feng He _{1,

2} , Zhenyu Wang ₂ , Liyuan Liang ₃

Affiliation

Sulfidation of nanoscale zerovalent iron (nZVI) can enhance particle performance. However, the underlying mechanisms of nZVI sulfidation are poorly known. We studied the effects of Fe²⁺ on 24-h dynamics of nZVI sulfidation by HS^– using a dosed S to Fe molar ratio of 0.2. This shows that in the absence of Fe²⁺, HS^– rapidly adsorbed onto nZVI particles and reacted with surface iron oxide to form mackinawite and greigite (<0.5 h). As nZVI corrosion progressed, amorphous FeS_x in solution deposited on nZVI, forming S-nZVI (0.5–24 h). However, in the initial presence of Fe²⁺, the rapid reaction between HS^– and Fe²⁺ produced amorphous FeS_x, which deposited on the nZVI and corroded the surface iron oxide layer (<0.25 h). This was followed by redeposition of colloidal iron (hydr)oxide on the particle surface (0.25–8 h) and deposition of residual FeS_x (8–24 h) on S-nZVI. S loading on S-nZVI was 1 order of magnitude higher when Fe²⁺ was present. Surface characterization of the sulfidated particles by TEM-SAED, XPS, and XAFS verified the solution dynamics and demonstrated that S^2– and S₂^2–/S_n^2– were the principal reduced S species on S-nZVI. This study provides a methodology to tune sulfur loading and S speciation on S-nZVI to suit remediation needs.

中文翻译：

硫化物硫化纳米零价铁：二价铁的动态过程、机理和作用

纳米级零价铁 (nZVI) 的硫化可以增强颗粒性能。然而，nZVI 硫化的潜在机制尚不清楚。我们研究了 Fe ²⁺对 HS 硫化 nZVI 24 小时动力学的影响^-使用剂量为 0.2 的 S 与 Fe 摩尔比。这表明，在没有Fe ²⁺的情况下，HS ^-快速吸附到nZVI颗粒上，并与表面氧化铁反应，形成硅镁石和镁灰石(<0.5 h)。随着nZVI腐蚀的进行，溶液中的非晶态FeS _x沉积在nZVI上，形成S-nZVI（0.5-24小时）。然而，在Fe ²⁺初始存在的情况下，HS ^-和Fe ²⁺之间的快速反应产生非晶态FeS _x ，其沉积在nZVI上并腐蚀表面氧化铁层(<0.25 h)。随后胶体氧化铁（氢）重新沉积在颗粒表面（0.25-8 小时），残留的 FeS _x沉积（8-24 小时）在 S-nZVI 上。当存在 Fe ²⁺时，S-nZVI 上的 S 负载量高出 1 个数量级。通过 TEM-SAED、XPS 和 XAFS 对硫化颗粒进行表面表征，验证了溶液动力学，并证明 S ^2–和 S ₂ ^2– /S _n ^2–是 S-nZVI 上主要的还原 S 物种。本研究提供了一种调整 S-nZVI 上的硫负载和 S 形态以满足修复需求的方法。

更新日期：2024-09-12

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南