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| Titel |
Transport and Retention of Stabilized Silver Nanoparticles in Water-Saturated Porous Media |
| VerfasserIn |
Yan Liang, Scott A. Bradford, Jiri Simunek, Harry Vereecken, Erwin Klumpp |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250076661
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| Zusammenfassung |
| Water-saturated column experiments were conducted to investigate the transport and retention
of surfactant stabilized silver nanoparticles (AgNPs) in quartz sand. The mobility of AgNPs
was enhanced with an increase in water velocity, sand grain size, and AgNP input
concentration (Co), and a decrease in solution ionic strength (IS). Retention profiles (RPs) for
AgNPs exhibited uniform, nonmonotonic, or hyperexponential shapes depending on
physicochemical conditions. The experimental breakthrough curves (BTCs) and RPs were
described using a numerical model that considers time/concentration- and depth-dependent
retention. The simulated maximum retained concentration on the solid phase (Smax) and the
retention rate coefficient (k1) increased with IS and as the grain size and/or Co decreased.
The RPs were more hyperexponential in finer textured sand and at lower Co, were
nonmonotonic or uniform at higher Co and in coarser sand, and tended to exhibit higher
peak concentrations in the RPs at lower velocities and at higher solution IS. These
observations indicate that uniform and nonmonotonic RPs occurred under conditions when
Smax was approaching filled conditions. The sensitivity of the nonmonotonic RPs
to IS and velocity in coarser textured sand indicates that AgNPs were partially
interacting in a secondary minimum and largely irreversibly interacting in a primary
minimum associated with microscopic heterogeneity. The competitive retention of
AgNPs and surfactants close to the column inlet was observed when additional
surfactants were added into the system. Nonmonotonic RPs had peak concentrations at a
greater distance in the presence of larger amount of surfactant. This implies that the
existence of natural occurring organic matter will likely facilitate NP transport deeper
into the subsurface environment and increase the risk potential of ground water
contamination.
Y. Liang, S. A. Bradford, J. Simunek, H.Vereecken, E. Klumpp. Sensitivity of the
Transport and Retention of Stabilized Silver Nanoparticles to Physicochemical Factors. Water
Research. Submitted. |
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