Emerging investigator series: ion diffusivities in nanoconfined interfacial water films contribute to mineral carbonation thresholds,Environmental Science: Nano

当前位置： X-MOL 学术 › Environ. Sci.: Nano › 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.)

Emerging investigator series: ion diffusivities in nanoconfined interfacial water films contribute to mineral carbonation thresholds
Environmental Science: Nano ( IF 5.8 ) Pub Date : 2020-02-20 , DOI: 10.1039/c9en01382b
Quin R. S. Miller _{1,

2,

3,

4,

5} , John P. Kaszuba _{4,

5,

6,

7,

8} , Sebastien N. Kerisit _{1,

2,

3,

4} , H. Todd Schaef _{1,

2,

3,

4} , Mark E. Bowden _{2,

3,

4,

9} , B. Peter McGrail _{2,

3,

4,

10} , Kevin M. Rosso _{1,

2,

3,

4}

Affiliation

The dynamics and reactivity of nanoconfined fluids play critical roles across a wide range of environmental and technological systems, though reaction mechanisms and kinetics are not well understood. The carbonation kinetics of forsterite (Mg₂SiO₄) exposed to 90 atm supercritical carbon dioxide at 35–65 °C and 85–100% relative humidity (RH) was monitored with in situ X-ray diffraction, and partner molecular dynamics simulations were used to describe the free energy landscape of Mg²⁺ adsorption and diffusion on forsterite surfaces covered in water films 3–10 monolayers thick. The collective findings reveal how decreasing the water film thickness by ∼1.4 monolayers, from ∼0.92 to ∼0.64 nm, inhibited reaction rates by up to 97%, promoted anhydrous Mg-carbonate (magnesite, MgCO₃) precipitation, and more than doubled the apparent activation energy of carbonation. The transport simulations suggest that four monolayers are required to enable sufficiently facile Mg²⁺ diffusion, helping explain previously observed water film thickness-dependent reactivity thresholds.

中文翻译：

新兴的研究人员系列：纳米受限界面水膜中的离子扩散性助长了矿物碳化阈值

纳米密闭流体的动力学和反应性在广泛的环境和技术系统中起着至关重要的作用，尽管对反应机理和动力学的了解还很少。通过原位X射线衍射监测在35–65°C和85–100％相对湿度（RH）下暴露于90 atm超临界二氧化碳的镁橄榄石（Mg ₂ SiO ₄）的碳酸化动力学，并进行了伙伴分子动力学模拟用于描述Mg ²⁺的自由能态在覆盖3-10个单层水膜的镁橄榄石表面上的吸附和扩散。集体发现揭示了如何将水膜厚度从约0.92 nm降低到约0.92 nm到约0.64 nm，如何抑制反应速率高达97％，促进无水碳酸镁（菱镁矿，MgCO ₃）的沉淀，并增加两倍以上。碳化的表观活化能。传输模拟表明需要四个单层才能使Mg ²⁺足够容易地扩散，从而有助于解释先前观察到的水膜厚度依赖性反应性阈值。

更新日期：2020-02-20

点击分享查看原文

点击收藏

阅读更多本刊最新论文