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

700347

Sigma-Aldrich

Titanium(IV) oxide, mixture of rutile and anatase, nanoparticles, <150 nm particle size (volume distribution, DLS), dispersion, 40 wt. % in H₂O, 99.5% trace metals basis

77627

Supelco

Poly(vinylpolypyrrolidone), ~110 μm particle size

02286

Sigma-Aldrich

Kollidon^® 25

1150706

USP

Crospovidone, United States Pharmacopeia (USP) Reference Standard

P2660000

Povidone, European Pharmacopoeia (EP) Reference Standard

1551503

USP

Povidone, United States Pharmacopeia (USP) Reference Standard

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

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

739421

Sigma-Aldrich

Silver nanowires, diam. × L 50 nm × 6 μm, 0.5% (isopropyl alcohol suspension)

735825

Sigma-Aldrich

Silver, conductive paste

265586

Sigma-Aldrich

Silver, wire, diam. 0.5 mm, ≥99.99% trace metals basis

265594

Sigma-Aldrich

Silver, wire, diam. 1.0 mm, ≥99.99% trace metals basis

267902

Sigma-Aldrich

Titanium, wire, diam. 0.81 mm, 99.7% trace metals basis

265527

Sigma-Aldrich

Silver, foil, thickness 0.1 mm, 99.9% trace metals basis

295744

Sigma-Aldrich

Silver, wool, diam. 0.05 mm, ≥99.9% trace metals basis

326976

Sigma-Aldrich

Silver, foil, thickness 2.0 mm, 99.9% trace metals basis

265608

Sigma-Aldrich

Silver, wire, diam. 1.0 mm, 99.9% trace metals basis

460400

Sigma-Aldrich

Titanium, wire, diam. 0.25 mm, 99.7% trace metals basis

IRMM531C

Titanium, IRMM^®, certified reference material, 0.5 mm wire

348791

Sigma-Aldrich

Titanium, foil, thickness 0.127 mm, 99.7% trace metals basis

204730

Sigma-Aldrich

Titanium(IV) oxide, rutile, 99.995% trace metals basis

204757

Sigma-Aldrich

Titanium(IV) oxide, rutile, ≥99.98% trace metals basis

224227

Sigma-Aldrich

Titanium(IV) oxide, rutile, powder, <5 μm, ≥99.9% trace metals basis

305812

Sigma-Aldrich

Titanium, 5-10 mm, ≥99.99% trace metals basis (purity exclusive of Na and K content)

369489

Sigma-Aldrich

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

266035

Sigma-Aldrich

Titanium, wire, diam. 1.0 mm, 99.99% trace metals basis

369438

Sigma-Aldrich

Silver, foil, thickness 1.0 mm, 99.99% trace metals basis

348848

Sigma-Aldrich

Titanium, foil, thickness 0.025 mm, 99.98% trace metals basis

P2472

Sigma-Aldrich

Povidone, meets USP testing specifications