title: Modeling the effects of water velocity on TiO2 nanoparticles transport in saturated porous media.
abstract: The transport of manufactured titanium dioxide (TiO2, rutile) nanoparticles (NP) in porous media was investigated under saturated conditions. Experiments were carried out with different fluid velocities, with values in the range of observed velocities in alluvial aquifers. As reported on the literature for different kinds of NPs, the amount of retained NPs decreased when the water velocity increased. Moreover, no retention was observed for ionic strength values smaller than 5mM. A transport model coupling convective-dispersive transport with a Langmuirian kinetic deposition was used to fit the BTCs. Empirical linear equations were developed to estimate the attachment rate ka and the maximal solid phase concentration smax. Both parameters were found to be linearly depending on the collector efficiency (η0). It was also observed that attachment efficiency (α) did not change with increase of water velocity under the given experimental conditions and that the model had a low sensitivity to α. Based on these estimates of the retention parameters, the classical dispersion-convection model coupled with a Langmuir type adsorption model was able to reproduce quite well the observed TiO2 breakthrough curves for every fluid velocity used in the experiments.
authors.affiliation: LHyGeS, UMR 7517 CNRS, Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex, France. Electronic address: ivan.toloni@etu.unistra.fr.
authors.forename: Ivan
authors.initials: I
authors.lastname: Toloni
authors.affiliation: LHyGeS, UMR 7517 CNRS, Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex, France.
authors.forename: François
authors.initials: F
authors.lastname: Lehmann
authors.affiliation: LHyGeS, UMR 7517 CNRS, Université de Strasbourg/EOST, 1 rue Blessig, 67084 Strasbourg Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ackerer
mesh_terms: D000327:Adsorption; D060587:Groundwater / Q000032:analysis*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000032:analysis*; D008962:Models, Theoretical; D009994:Osmolar Concentration; D016062:Porosity; D014025:Titanium / Q000032:analysis*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium
keywords: Attachment efficiency; Column experiments; Langmuirian kinetic; Retention; Single collector efficiency; Titanium dioxide