Effect of water chemistry and aging on iron-mica interaction forces: implications for iron particle transport.
Effect of water chemistry and aging on iron-mica interaction forces: implications for iron particle transport.
复制标题
DOI：
10.1021/la301539q
复制
发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
E. Pensini;C. Yip;D. O’Carroll;B. Sleep
中科院分区：
文献类型：
--
作者：
E. Pensini;C. Yip;D. O’Carroll;B. Sleep
颗粒通过地下水系统的运输受机械力和化学力的复杂相互作用的控制，这些力最终负责与地质基质结合。为了了解这些力量的背景下，零价铁颗粒用于地下水的修复，原子力显微镜（AFM）为基础的力谱被用来表征原子力显微镜与羰基铁颗粒（CIP）或电沉积铁作为一个函数的反价，温度，颗粒形态和年龄的修改的针尖之间的相互作用。测量的相互作用力总是吸引力的新鲜和老化的CIP和电沉积铁，除了在100 mM NaCl，作为带负电荷的云母和带正电荷的铁之间的静电吸引力的结果。在100 mM NaCl中，排斥水合力似乎占主导地位。实验数据与基于扩展DLVO（XDLVO）理论的预测结果吻合较好。通过X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和能量色散谱（EDS）评估老化对铁颗粒组成和形态的影响，揭示老化的颗粒包含被铁氧化物和氢氧化物的混合物钝化的零价铁核心。力谱表明，老化引起的变化，由于颗粒形态和接触面积的变化，在粘合力。
The transport of particles through groundwater systems is governed by a complex interplay of mechanical and chemical forces that are ultimately responsible for binding to geological substrates. To understand these forces in the context of zero valent iron particles used in the remediation of groundwater, atomic force microscopy (AFM)-based force spectroscopy was employed to characterize the interactions between AFM tips modified with either carbonyl iron particles (CIP) or electrodeposited Fe as a function of counterion valency, temperature, particle morphology, and age. The measured interaction forces were always attractive for both fresh and aged CIP and electrodeposited iron, except in 100 mM NaCl, as a consequence of electrostatic attraction between the negatively charged mica and positively charged iron. In 100 mM NaCl, repulsive hydration forces appeared to dominate. Good agreement was found between the experimental data and predictions based on the extended DLVO (XDLVO) theory. The effect of aging on iron particle composition and morphology was assessed by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) revealing that the aged particles comprising a zero valent iron core passivated by a mixture of iron oxides and hydroxides. Force spectroscopy showed that aging caused variations in the adhesive force due to the changes in particle morphology and contact area.