Sulfidation mechanisms of Fe(III)-(oxyhydr)oxide nanoparticles: a spectroscopic study
Sulfidation mechanisms of Fe(III)-(oxyhydr)oxide nanoparticles: a spectroscopic study
复制标题
DOI：
10.1039/c7en01109a
复制
发表时间：
2018-04-01
影响因子：
7.3
通讯作者：
Brown, Gordon E., Jr.
中科院分区：
文献类型：
--
作者：
Kumar, Naresh;Pacheco, Juan Lezama;Brown, Gordon E., Jr.
利用同步辐射X射线吸收光谱、透射电子显微镜和湿化学分析等方法，研究了不同S/Fe摩尔比的水铁矿、针铁矿和赤铁矿纳米颗粒与溶解硫化物在厌氧条件下反应的硫化机理和硫氧化产物。我们的研究结果表明，表面积本身并不能解释Fe（III）-（oxyhydr）氧化物纳米粒子与溶解的硫化物的反应性的差异;原子级表面结构的差异也可能发挥重要作用。与针铁矿和赤铁矿相比，水铁矿的较高反应性导致更快的硫化速率。我们发现，多硫化物以及元素硫的硫化的所有三个Fe（III）-（oxyhydr）氧化物纳米粒子的研究中的主要反应产物。我们还发现，在针铁矿和赤铁矿的硫化过程中形成了硫代硫酸盐和硫酸盐，但在水铁矿的情况下没有形成，这表明针铁矿和赤铁矿较慢的反应动力学有利于固相硫代硫酸盐和元素硫的形成在我们的实验中。此外，我们的研究结果表明，在硫化反应中的S/Fe比是一个关键变量。发现水铁矿、针铁矿和赤铁矿纳米颗粒的铁溶解速率增加至高达100%的S/Fe比。
We used synchrotron-based X-ray absorption spectroscopy, transmission electron microscopy, and wet chemical analyses to study the sulfidation mechanism(s) and sulfur oxidation products from the reaction of ferrihydrite, goethite, and hematite nanoparticles with dissolved sulfide at different S/Fe molar ratios under anaerobic condition. Our results suggest that surface area alone does not explain the differences in reactivity of Fe(III)-(oxyhydr)oxide nanoparticles with dissolved sulfides; differences in atomic-level surface structure are also likely to play an important role. The higher reactivity of ferrihydrite leads to a faster sulfidation rate compared to that of goethite and hematite. We found that polysulfides as well as elemental sulfur are the major reaction products in the sulfidation of all three Fe(III)-(oxyhydr) oxide nanoparticles studied. We also found that thiosulfate and sulfate formed during the sulfidation of goethite and hematite but did not form in the case of ferrihydrite, suggesting that the slower reaction kinetics of goethite and hematite favors the formation of solid-phase thiosulfates and elemental sulfur in our experiments. In addition, our results revealed that the S/Fe ratio is a critical variable in the sulfidation reaction. Iron dissolution rates for ferrihydrite, goethite, and hematite nanoparticles were found to increase up to a S/Fe ratio of