A systematic evaluation of agglomeration of Ag and TiO2 nanoparticles under freshwater relevant conditions.

A systematic evaluation of agglomeration of Ag and TiO2 nanoparticles under freshwater relevant conditions.

Environmental pollution (Barking, Essex : 1987) (2014-07-08)

Emel Topuz, Laura Sigg, Ilhan Talinli

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.

MATERIALS

Product Number

Brand

Product Description

02286

Sigma-Aldrich

Kollidon^® 25

637254

Sigma-Aldrich

Titanium(IV) oxide, anatase, nanopowder, <25 nm particle size, 99.7% trace metals basis

637262

Sigma-Aldrich

Titanium(IV) oxide, rutile, nanopowder, <100 nm particle size, 99.5% trace metals basis

634662

Sigma-Aldrich

Titanium(IV) oxide, mixture of rutile and anatase, nanopowder, <100 nm particle size (BET), 99.5% trace metals basis

P2660000

Povidone, European Pharmacopoeia (EP) Reference Standard

635057

Sigma-Aldrich

Titanium(IV) oxide, rutile, <001>, (single crystal substrate), ≥99.9% trace metals basis, L × W × thickness 10 mm × 10 mm × 0.5 mm

369489

Sigma-Aldrich

Titanium, foil, thickness 2.0 mm, 99.7% trace metals basis

GF93461700

Silver, foil, 4mm disks, thickness 0.1mm, as rolled, 99.95+%

GF95768409

Silver, foil, 6mm disks, thickness 0.008mm, 99.95+%

GF66944740

Silver, foil, 6mm disks, thickness 0.02mm, 99.97%

GF75373421

Silver, foil, 2m coil, thickness 0.025mm, as rolled, 99.95+%

GF91393005

Silver, foil, 6mm disks, thickness 0.008mm, 99.97%

GF91672139

Titanium, wire reel, 20m, diameter 0.05mm, hard, 99.8%

GF71330767

Silver, foil, 25mm disks, thickness 0.007mm, 99.97%

GF91204466

Titanium, wire reel, 5m, diameter 1.0mm, as drawn, 99.6+%

GF85283400

Silver, foil, 25mm disks, thickness 0.5mm, as rolled, 99.95+%

GF96391402

Titanium, wire reel, 25m, diameter 0.20mm, annealed, 99.6+%

GF69098956

Silver, foil, 4mm disks, thickness 0.5mm, as rolled, 99.99+%

GF92849417

Silver, foil, 4mm disks, thickness 1.0mm, as rolled, 99.95+%

PHR1250

Supelco

Povidone, Pharmaceutical Secondary Standard; Certified Reference Material

GF93908065

Silver, foil, 15mm disks, thickness 1.0mm, as rolled, 99.95+%

GF82877035

Silver, foil, 1m coil, thickness 0.035mm, as rolled, 99.95+%

GF94150593

Titanium, wire reel, 10m, diameter 1.5mm, as drawn, 99.6+%

GF82635138

Titanium, tube, 500mm, outside diameter 6.35mm, inside diameter 5.53mm, wall thickness 0.41mm, annealed, 99.6+%

GF97204990

Titanium, wire reel, 100m, diameter 0.25mm, annealed, 99.6+%

GF71783354

Titanium, wire reel, 100m, diameter 0.75mm, as drawn, 99.6+%

GF72193114

Titanium, tube, 500mm, outside diameter 2.03mm, inside diameter 1.63mm, wall thickness 0.2mm, annealed, 99.6+%

GF84917188

Titanium, wire reel, 1m, diameter 0.25mm, as drawn, 99.99+%

GF71020235

Titanium, wire reel, 0.5m, diameter 1.0mm, as drawn, 99.6+%

GF75222547

Silver, foil, 25mm disks, thickness 0.5mm, as rolled, 99.99+%