title: Enhanced transportability of zero valent iron nanoparticles in aquifer sediments: surface modifications, reactivity, and particle traveling distances.
abstract: In this study, we assessed the transportability of zero valent iron nanoparticles (nano-Fe0) coated with different organics (carboxy methyl cellulose (CMC), poly acrylic acid (PAA), and xanthan gum) in standard porous sand and in real aquifer sediments. Our results suggest that the organic surface coatings optimized for nano-Fe0in porous sand media do not necessarily reflect the same transportability in real field aquifer sediment. Xanthan gum-coated nano-Fe0showed highest transportability in standard porous sand, but the performance was much lower in real aquifer sediment, whereas the PAA-coated nano-Fe0particle showed better transportability both in aquifer sediment and in porous sand media. Nano-Fe0without organic surface coating exhibited very low transportability and was largely retained by the porous medium. Our results suggest that the molecular weight and surface charge density of the organic may play a role in transportability of these nanoparticles. To assess the impact of organic coating on the nanoparticle reactivity with contaminants, we also conducted batch tests to follow TCE degradation using different surface coatings and found no significant difference albeit a minor delay in kinetics. Using theoretical calculations, we also estimated the potential distance traveled by nanoparticles in porous sand as well as in aquifer sediment. Our results suggest that using xanthan gum and PAA as surface coating, nano-Fe0could travel up to 9.8 and 4.1 m, respectively, in the porous sand media as compared to 0.2 and 0.9 m in real aquifer sediment, respectively. Graphical abstract Nanoparticle mobility in porous sand vs and aquifer sediment.
authors.affiliation: CEREGE, CNRS Aix Marseille Université-IRD-Collège de France, UM 7330, 13545, Aix-en-Provence, France. nareshk@stanford.edu.|International Consortium for the Environmental Implications of Nanotechnology iCEINT, Aix-en-Provence, France. nareshk@stanford.edu.|Department of Geological Sciences, Stanford University, Stanford, CA, 94305, USA. nareshk@stanford.edu.
authors.forename: Naresh
authors.initials: N
authors.lastname: Kumar
authors.affiliation: CEREGE, CNRS Aix Marseille Université-IRD-Collège de France, UM 7330, 13545, Aix-en-Provence, France.|International Consortium for the Environmental Implications of Nanotechnology iCEINT, Aix-en-Provence, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Labille
authors.affiliation: CEREGE, CNRS Aix Marseille Université-IRD-Collège de France, UM 7330, 13545, Aix-en-Provence, France.|International Consortium for the Environmental Implications of Nanotechnology iCEINT, Aix-en-Provence, France.
authors.forename: Nathan
authors.initials: N
authors.lastname: Bossa
authors.affiliation: CEREGE, CNRS Aix Marseille Université-IRD-Collège de France, UM 7330, 13545, Aix-en-Provence, France.|International Consortium for the Environmental Implications of Nanotechnology iCEINT, Aix-en-Provence, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Auffan
authors.affiliation: Aix Marseille Université, CNRS, LCE, FRE 3416, Bâtiment Villemin, Europôle de l'Arbois, Avenue Louis Philibert, BP 80, 13545, Aix en Provence, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Doumenq
authors.affiliation: CEREGE, CNRS Aix Marseille Université-IRD-Collège de France, UM 7330, 13545, Aix-en-Provence, France.|International Consortium for the Environmental Implications of Nanotechnology iCEINT, Aix-en-Provence, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Rose
authors.affiliation: CEREGE, CNRS Aix Marseille Université-IRD-Collège de France, UM 7330, 13545, Aix-en-Provence, France.|International Consortium for the Environmental Implications of Nanotechnology iCEINT, Aix-en-Provence, France.
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Bottero
mesh_terms: D060587:Groundwater; D007501:Iron; D053768:Metal Nanoparticles; D053758:Nanoparticles; D016062:Porosity; D012822:Silicon Dioxide
chemical_list: D012822:Silicon Dioxide; D007501:Iron
keywords: Nanoparticle mobility; PAA; Porous media; Surface coating; Xanthan gum; Zero valent iron nanoparticles