The extensive use of nanoscale zero-valent iron (nZVI) particles for groundwater treatment has been limited, in part, because of their non-selective reactivity and low mobility in aquatic environments. Herein, we describe and explore progressive changes in the reactivity and migration of aqueous dispersed nZVI particles under an applied DC electric field. Due to the applied electric field with an intensity of about 1 V cm-1, the solution oxidation-reduction potential (ORP) remained as low as -200 mV for at least 32 days, which was in agreement with the persistence of the reduced iron species (mainly Fe(II)), and led to substantially prolonged reactivity of the original nZVI. The treatment of chlorinated ethenes (DCE > PCE > TCE) was markedly faster, individual CHC compounds were eliminated with the same kinetics and no lesser-chlorinated intermediates were accumulated, following thus the direct dechlorination scheme. When nZVI-dispersion flows towards the anode through vertical laboratory columns filled with quartz sand, significant enhancement of nZVI migration was recorded because of lower extent of nanoparticle aggregation and increased repulsion forces between the nanoparticles and the surface of silica dioxide. The results of this study have significant consequences for groundwater remediation, mainly for the treatment of slowly degradable DCE in real CHC contaminated groundwater, where it could improve the reactivity, the longevity and the migration of nZVI particles.

Geosyntec Consultants 7 Graphics Drive Ewing NJ USA

Institute for Nanomaterials Advanced Technologies and Innovation Technical University of Liberec Studentská 2 CZ 46117 Liberec Czech Republic

MEGA a s Pod Vinicí 87 CZ 47127 Stráž pod Ralskem Czech Republic

Regional Centre of Advanced Technologies and Materials Palacký University Olomouc Šlechtitelů 27 CZ 78371 Olomouc Czech Republic

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