Environmental Engineering Reference
In-Depth Information
Chapter 14
Dielectrophoresis Used for Nanoparticle
Manipulation in Microfluidic Devices
Mihai Lungu, Madalin Bunoiu, and Adrian Neculae
Abstract Nano-sized particles have received considerable interest in the past two
decades. The filtration of nanoparticles is becoming an important issue as they are
produced in large numbers from material synthesis or combustion emission, and
their effect on human health is relatively high. Dielectrophoresis (DEP), phenom-
enon that induces spatial movement of particles placed in nonuniform electric field,
depending on the dielectric properties of the particles and the surrounding medium,
the geometry of the electrodes, and the amplitude and frequency of the applied
signal, proved to be the most adequate tool in order to manipulate particles at
submicron scale. First, this work presents an overview of the various applications of
the dielectrophoresis. Next, the theoretical description of the main forces implied in
the spatial control of submicron particles is given. Finally, a mathematical model
describing the filtration of nanoparticles suspended in flue gas by a combination of
dielectrophoretic and electrohydrodynamic forces, and a set of numerical results
obtained by simulations performed in the frame of this model are presented. The
dielectrophoretic force and the nanoparticles concentration profile in a DEP-based
separation micro system consisting of a micro channel are numerically investigated
using the COMSOL Multiphysics finite element code. The performances of the
filtration device are analyzed in terms of a specific quantity related to the separation
process, called
Filtration rate
. The simulations provide the optimal set of values for
the control parameters of the separation process in order to obtain a desired
performance, and represent a useful tool in designing of microfluidic devices for
separating nanoparticles from flue gas.
