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Publication
Numerical prediction of diffusion and electric field-induced iron nanoparticle transport
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Advisor(s)
Abstract(s)
Zero valent iron nanoparticles (nZVI) are considered very promising for the remediation of contaminated
soils and groundwaters. However, an important issue related to their limited mobility remains unsolved.
Direct current can be used to enhance the nanoparticles transport, based on the same principles of
electrokinetic remediation. In this work, a generalized physicochemical model was developed and solved
numerically to describe the nZVI transport through porous media under electric field, and with different
electrolytes (with different ionic strengths). The model consists of the Nernst–Planck coupled system of
equations, which accounts for the mass balance of ionic species in a fluid medium, when both the
diffusion and electromigration of the ions are considered. The diffusion and electrophoretic transport of
the negatively charged nZVI particles were also considered in the system. The contribution of
electroosmotic flow to the overall mass transport was included in the model for all cases. The nZVI
effective mobility values in the porous medium are very low (10 7
–10 4 cm2V 1 s 1
), due to the
counterbalance between the positive electroosmotic flow and the electrophoretic transport of the
negatively charged nanoparticles. The higher the nZVI concentration is in the matrix, the higher the
aggregation; therefore, low concentration of nZVI suspensions must be used for successful field
application.
Description
Keywords
Electrokinetics nZVI Porous media Electrolytes Nernst–Planck equations
