斯麦克提特粘土-泽奥利特复合材料中受限反应水的动力学
Michael C Pitman1, Adri C T van Duin
1Soft Matter Theory and Simulations Group, Computational Biology Center, IBM Watson Research Center, Yorktown Heights, New York 10598, USA. pitman@us.ibm.com
Journal of the American Chemical Society
|January 12, 2012
概括
在密集的矿物环境中的水动力学,如粘土和地质石,对于资源管理至关重要. 这项研究揭示了水的流动性在与水合物复合时与自由扩散时显著不同,影响了放射性废物制和海水淡化等过程.
科学领域:
- 地质化学 地质化学
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
背景情况:
- 限制在中孔矿物质 (粘土,地质石) 中的水是资源管理 (废物制,海水淡化,石油回收) 的关键.
- 了解这些复杂环境中的水动力学对于预测和控制相关过程至关重要.
研究的目的:
- 通过使用大规模原子模型,研究粘土和石复合环境中的水动力学.
- 探索反应性表面化学对不同温度的水流动性的影响.
主要方法:
- 使用ReaxFF反应力场的大型原子模型.
- 模拟的水动力学在斯麦克提特粘土限制在一个石子在300-647K的温度范围内.
- 分析了新出现的表面化学物质,包括酸平衡和西兰醇形成.
主要成果:
- 在化后的粘土模型中观察到不同的水化结构 (单层和双层).
- 发现粘土的水化产生了石的水负荷.
- 水的动态,包括速度和温度的依赖性,与实验中子散射和脉冲场梯度数据保持一致.
- 从表面吸附和化物受限水中的介层Ca(OH) ((2) ·nH(2) O中区分水动力学.
结论:
- 与水合物复合的水表现出明显较慢的扩散比自由水.
- 减少移动性归因于Arrhenius预指数因子的差异,而不是激活能量.
- 提供了对复杂矿泉水系统中水的行为进行原子学的洞察.
相关概念视频
Hydration of Cement
Hydration of cement is a chemical reaction between cement particles and water. This process occurs primarily through two mechanisms: through-solution and topochemical. In the through-solution process, anhydrous compounds dissolve into their constituents, hydrates form in the solution, and then precipitate from the supersaturated solution. The topochemical process involves solid-state reactions at the cement particle surface. The through-solution process dominates the topochemical process at the...
Permeability of Concrete
Permeability in the context of concrete refers to how easily liquids or gases can pass through the material. This quality is crucial for assessing the water-tightness and durability of concrete structures and their resistance to chemical attacks. Concrete permeability can be determined through comparative laboratory tests. These tests typically involve sealing a concrete specimen from the sides, applying water pressure to the top surface with pressure, and measuring the amount of water passing...
Porosity in Cement Paste
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is critical—it...
The balance of water to cement in the mix is critical—it...
Alkali Aggregate Reaction in Concrete
The alkali-aggregate reaction in concrete involves natural siliceous minerals in aggregates reacting with alkaline hydroxides derived from cement alkalis. This reaction forms an alkali-silica gel that absorbs water, swells, and increases in volume, which is confined by the surrounding cement paste, creating internal pressures that crack and disrupt the concrete. The extent of expansion and damage can be partly attributed to the alkali-silica reaction's osmotic hydraulic pressure and the...


