Dielectrophoretic Particle Chromatography (DPC) with scalable separation effect at preparative scale

从液体介质中分离微米和亚微米颗粒或根据特定性质对其进行分级对于各种应用至关重要。颗粒分离在（生物）分析、医疗诊断、材料回收、产品质量提高或提高工业过程的成本效益等方面都是关键。例如，为了从废料中回收贵金属，废料首先被研磨以产生较小的碎片，这些碎片可以根据密度、磁性或其他特性用标准方法分离。然而，大多数贵金属都集中在作为副产品产生的细粉尘中，这些粉尘太小而无法进行有效的分馏。分选这种小的亚微米或微米颗粒的标准方法是例如凝胶电泳或尺寸排阻色谱法。然而，这些方法每批只能处理少量，并且所得馏分的回收在成本和时间上都是密集的。这实际上限制了这些技术的分析应用。当处理小于10 µm的颗粒时，其他用于更高通量的连续分级方法，如场流分级或离心，会失去选择性和效率。介绍了介电泳粒子色谱法。该方法使用介电电泳，一种交流电动效应，根据色谱柱中的特定性质来增加目标颗粒的停留时间：颗粒混合物将根据其极化率不同地与叠加的不均匀交流电场相互作用，这是一种取决于颗粒形式，尺寸和材料的颗粒性质。不均匀的交流电场是由两个同心的电极形成的。该环形空间填充有电介质填充床（例如，石英球），其散射同心电极的电场并产生局部不均匀性。与常规微流体介电泳分离器相比，这样的布置允许高几个数量级的通量。所施加的交流场在其频率上进行调制，以针对频率相关的粒子极化率的特定差异。为了更好地了解潜在的传输机制，并设计一个介电泳色谱柱，可以在工业相关的吞吐量，微通道以及宏观填充床列将进行调查。将使用模拟和实验方法进行详细的参数变化研究（关于施加的场强、频率、填充和通道几何形状以及调制频率）。该项目的目的是实现一个介电泳色谱柱的连续多维分馏的颗粒在液相中的吞吐量高达每小时10克。

The separation of micron and submicron particles from a liquid medium or their fractionation according to specific properties is essential for a variety of applications. Particle separation is key, for instance, in (bio-) analytics, medical diagnostic, material recycling, product quality enhancement, or to improve the cost efficiency of industrial processes. As an example, to recover precious metals from scrap, the scrap is firstly milled to produce smaller pieces that could be separated with standard methods according to density, magnetism, or other properties. Most of the precious metal, however, is concentrated in the fine dust that is produced as a byproduct and which is too small for an effective fractionation. Standard methods to sort such small submicron or micro particles are for example gel electrophoresis or size exclusion chromatography. These methods, however, can only process small quantities per batch and the recovery of the resulting fractions is intensive in both cost and time. This effectively limits those techniques to analytical application. Other continuous fractionation approaches for higher throughputs, such as field flow fractionation or centrifugation lose both selectivity and efficiency when processing particles smaller than 10 µm. Here, dielectrophoretic particle chromatography is introduced. This methods uses dielectrophoresis, an ac electrokinetic effect, to increase the residence time of target particles according to specific properties in a chromatography column: Particle mixtures will interact with a superimposed inhomogeneous ac electric field differently according to their polarizability, which is a particle property that depends on particle form, size and material. The inhomogeneous ac field is created by two concentric electrodes which form an annulus. The annulus is filled with a dielectric packed-bed (e.g., of quartz spheres) that scatters the electric field of the concentric electrodes and creates local inhomogeneities. Such an arrangement allows for several orders of magnitude higher throughput compared to conventional microfluidic dielectrophoretic separators. The applied ac field is modulated in its frequency in order to target specific differences in the frequency-dependent particle polarizability. To better understand the underlying transport mechanisms and to design a dielectrophoretic chromatography column that can operate at industrially relevant throughputs, both microchannels as well as macroscopic packed-bed columns will be investigated. A detailed parameter variation study (regarding applied field strength, frequency, packing and channel geometry, as well as modulation frequency) will be conducted using both simulation and experimental methods. Aim of this project is the implementation of a dielectrophoretic chromatography column for a continuous multi-dimensional fractionation of particles in the liquid phase at throughputs of up to 10 g per hour.