title: A systematic evaluation of agglomeration of Ag and TiO2 nanoparticles under freshwater relevant conditions.
abstract: This study aims to investigate effects of freshwater components in order to predict agglomeration behavior of silver nanoparticles coated with citrate (AgNP-Cit), polyvinylpyrrolidone (AgNP-PVP), and of TiO2 nanoparticles. Agglomeration studies were conducted in various media based on combinations of ions, natural organic matter (humic, fulvic acid) and surfactants (sodium dodecyl sulfate, alkyl ethoxylate), at a constant ionic strength of 10 mM over time for up to 1 week. Agglomeration level of AgNP-Cit and TiO2 was mostly dependent on the concentration of Ca(2+) in media, and their size strongly increased to micrometer scale over 1 week. However, AgNP-Cit and TiO2 were stabilized to particle size around 500 nm in the presence of NOM, surfactants and carbonate over 1 week. AgNP-PVP maintained their original size in all media except in the presence of Mg(2+) ions which led to significant agglomeration. Behavior of these engineered nanoparticles was similar in a natural freshwater medium.
authors.affiliation: Eawag - Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; Istanbul Technical University, Environmental Engineering Department, Maslak, Istanbul 34469, Turkey. Electronic address: topuze@itu.edu.tr.
authors.forename: Emel
authors.initials: E
authors.lastname: Topuz
authors.affiliation: Eawag - Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland. Electronic address: laura.sigg@eawag.ch.
authors.forename: Laura
authors.initials: L
authors.lastname: Sigg
authors.affiliation: Istanbul Technical University, Environmental Engineering Department, Maslak, Istanbul 34469, Turkey. Electronic address: talinli@itu.edu.tr.
authors.forename: Ilhan
authors.initials: I
authors.lastname: Talinli
mesh_terms: D001578:Benzopyrans / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry*; D005618:Fresh Water / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D009994:Osmolar Concentration; D010316:Particle Size; D011205:Povidone / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D001578:Benzopyrans; D002254:Carbonates; D007477:Ions; C009495:titanium dioxide; D019343:Citric Acid; D012834:Silver; D014025:Titanium; D011205:Povidone; C005023:fulvic acid
keywords: Agglomeration; Engineered nanoparticles; Natural organic matter; Surfactant