Technical University of Liberec, Institute of Novel Technologies and Applied Informatics, Liberec, Czech Republic.
Nanoscale Res Lett. 2011 Sep 14;6(1):527. doi: 10.1186/1556-276X-6-527.
Zero-valent iron nanoparticles rapidly aggregate. One of the reasons is magnetic forces among the nanoparticles. Magnetic field around particles is caused by composition of the particles. Their core is formed from zero-valent iron, and shell is a layer of magnetite. The magnetic forces contribute to attractive forces among the nanoparticles and that leads to increasing of aggregation of the nanoparticles. This effect is undesirable for decreasing of remediation properties of iron particles and limited transport possibilities. The aggregation of iron nanoparticles was established for consequent processes: Brownian motion, sedimentation, velocity gradient of fluid around particles and electrostatic forces. In our previous work, an introduction of influence of magnetic forces among particles on the aggregation was presented. These forces have significant impact on the rate of aggregation. In this article, a numerical computation of magnetic forces between an aggregate and a nanoparticle and between two aggregates is shown. It is done for random position of nanoparticles in an aggregate and random or arranged directions of magnetic polarizations and for structured aggregates with arranged vectors of polarizations. Statistical computation by Monte Carlo is done, and range of dominant area of magnetic forces around particles is assessed.
零价铁纳米颗粒迅速聚集。其中一个原因是颗粒之间的磁力。颗粒周围的磁场是由颗粒的组成引起的。它们的核心由零价铁形成，外壳是一层磁铁矿。磁力有助于颗粒之间的吸引力，导致纳米颗粒聚集增加。这种效应不利于降低铁颗粒的修复性能和限制其传输可能性。铁纳米颗粒的聚集是通过连续的过程建立的：布朗运动、沉降、颗粒周围流体的速度梯度和静电力。在我们之前的工作中，介绍了颗粒之间磁力对聚集的影响。这些力对聚集速度有重大影响。在本文中，展示了对团聚体和纳米颗粒之间以及两个团聚体之间的磁力的数值计算。对于团聚体中纳米颗粒的随机位置以及磁极化的随机或排列方向以及具有排列的极化矢量的结构化团聚体进行了计算。通过蒙特卡罗进行了统计计算，并评估了颗粒周围磁力的主导区域范围。
