Home > Publications database > Transport, co-transport, and retention of functionalized multi-walled carbon nanotubes in porous media |
Book/Dissertation / PhD Thesis | FZJ-2017-02353 |
2016
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
ISBN: 978-3-95806-198-9
Please use a persistent id in citations: http://hdl.handle.net/2128/14048 urn:nbn:de:0001-2017032864
Abstract: The information on transport and retention behavior of functionalized multiwalled carbon nanotubes (MWCNTs) in porous media is essential for environmental protection and remediation due to the wide applications of MWCNTs and lack of disposal regulations. The aim of this study is therefore to investigate: i) the attachment, transport, retention and remobilization of $^{14}$C-labeled functionalized MWCNTs indifferent porous media (quartz sand (QS), goethite-coated quartz sand (GQS), and soil), ii) co-transport of pollutants (chlordecone (CLD) and sulfadiazine (SDZ)) byMWCNTs, and iii) the role of surfactant on MWCNTs transport as a modeled soilremediation process, based on column and batch experiments at the environmentally relevant concentrations under various physiochemical conditions. The breakthrough curves (BTCs) and retention profiles (RPs) were determined and simulated based on advective- dispersive equation by using different numerical models that considered both time- and depth- dependent blocking functions. The effect of goethite coating on MWCNTs transport was conducted in mixtures of negatively charged QS and positively charged GQS. The linear equilibrium sorption model provided a good description of batch results, and the distribution coefficients (KD) drastically increased with the GQS fraction that was electrostatically favorable for retention. Similarly, retention of MWCNTs increased with the GQS fraction in packed column experiments. However, calculated values ofKD on GQS were around two orders of magnitude smaller in batch than packed column experiments due to differences in lever arms associated with hydrodynamic and adhesive torques at microscopic roughness locations. Furthermore, the fraction of the chemically heterogeneous sand surface area that was favorable for retention was much smaller than the GQS fraction, presumably because nanoscale roughness produced shallow interactions that were susceptible to removal. These observations indicated that only a minor fraction of the GQS was favorable for MWCNT retention. These same observations held for several different sand sizes. [...]
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