Project Details
Projekt
Highly permeable, electrically switchable filter for multi-dimensional sorting of suspended submicron particles
Applicant
Professor Dr.-Ing. Jorg Thöming
Subject Area
Mechanical Process Engineering
Chemical and Thermal Process Engineering
Chemical and Thermal Process Engineering
Term
from 2017 to 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 382080004
The sorting of suspended nano- and submicroparticles with respect to conductivity and geometry at technically relevant throughputs is still an unresolved problem. Important challenges here are potential disturbances that typically interfere with the separation mechanism. This is, because small particles are prone to diffusion and thermal convection, whereby conventional fractionation processes often lose their selectivity, especially at particle diameter below 10 µm. The aim of this project is to achieve multidimensional separations of particles below 5 µm down to the nanometer scale by material, shape and size, preferably in one device with separation efficiencies above 80 % and technically relevant throughputs (500 mL/h). For this purpose, an electrodeless dielectrophoretic (ELD) filtration system will be developed, in which particle sorting is carried out by an electrically switchable, selective particle retention in local maxima of alternating electric fields. The mechanism is based on the frequency-dependent polarization of particles and the surrounding medium in an inhomogeneous electric field generated by electrically insulating structures between widely spaced external electrodes. A dielectrophoretic (DEP) force acts on the particle, which depends on the particle size, shape and its dielectric properties as well as on process parameters such as the applied field strength and frequency.In the first funding period it was shown that a material- and size-selective separation of microparticles (<10 µm) is possible in electrically switchable ELD filters with separation efficiencies above 90 %. A model was developed that describes the behavior of micro- and submicron particles both in ELD filters manufactured in chip technology and in filters with three orders of magnitude higher throughput. The aim of the second funding period is to apply the design criteria determined for multidimensional particle sorting. Under the influence of a high-frequency electric field, particles below 5 µm down to the nanometer scale should be material-selectively separated at technically relevant throughputs and then shape- or size-specifically remobilised by means of a changed field frequency or by turning the electric field off.
DFG Programme
Priority Programmes
