Enhanced Transport and Transformation of Zerovalent Nanoiron in Clay Using Direct Electric Current
One of the major obstacles to zerovalent iron nanoparticles (nZVI) application in soil and groundwater remediation is the limited transport, especially in low-permeability soils. In this study, direct current (constant potential of 5.0 V) was used to enhance polymer-coated nZVI mobility in different porous media, including a bed of glass beads and kaolin clay. The tests were conducted using a modified electrophoretic cell and with nZVI concentrations typical of field applications (4 g L−1). Experimental results indicate that the use of direct current can enhance the transport of the polymer-modified nanoparticles when compared with natural diffusion in low permeability or surface neutral porous medium. The applied electric field appeared to enhance the oxidation–reduction potential, creating a synergistic effect of nZVI usage with electrokinetics. Aggregation of the nanoparticles, observed near the injection point, remained unresolved.
KeywordsZerovalent iron nanoparticles (nZVI) Enhanced transport Direct current Electrokinetics Electrochemical treatment
This work has been funded by the European Regional Development Fund (ERDF) through COMPETE—Operational Program for Competitiveness Factors (OPCF), by Portuguese National funds through “FCT—Fundação para a Ciência e a Tecnologia” under project «PTDC/AGR-AAM/101643/2008 NanoDC», by the research grant SFRH/BD/76070/2011, by FP7-PEOPLE-IRSES-2010-269289-ELECTROACROSS and by RIARTAS-Red Iberoamericana de aprovechamiento de residuos industriales para el tratamiento de suelos y aguas contaminadas, Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (Cyted). The Department of Civil and Environmental Engineering at Lehigh University is acknowledged, where all the equipment development, testing, and analysis for this work were funded. Dan Zeroka is kindly acknowledged for the electrophoretic cell modification.
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