Silicon impurity release and surface transformation of TiO2 anatase and rutile nanoparticles in water environments.

Silicon impurity release and surface transformation of TiO2 anatase and rutile nanoparticles in water environments.

Environmental pollution (Barking, Essex : 1987) (2013-11-05)

Xuyang Liu, Gexin Chen, Justin G Erwin, Chunming Su

ABSTRACT

Surface transformation can affect the stability, reactivity, and toxicity of titanium dioxide (TiO2) nanoparticles (NPs) in water environments. Herein, we investigated the release kinetics of Si impurity frequently introduced during NP synthesis and the resulting effect on TiO2 NP transformation in aqueous solutions. The release of Si increased from 2 h to 19 d at three pHs with the order: pH 11.2 ≥ pH 2.4 > pH 8.2. The Si release process followed parabolic kinetics which is similar to diffusion controlled dissolution of minerals, and the release magnitude followed the order: 10 × 40 nm rutile > 50 nm anatase > 30 × 40 nm rutile. FTIR data indicated preferential dissolving of less polymerized Si species on NP surface. Surface potential and particle size of TiO2 NPs remained almost constant during the 42-day monitoring, implying the unaffected stability and transport of these NPs by the incongruent dissolution of impurities.

MATERIALI

N° Catalogo

Marchio

Descrizione del prodotto

718467

Sigma-Aldrich

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637254

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

232033

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Titanium(IV) oxide, anatase, powder, 99.8% trace metals basis

14021

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Titanium(IV) oxide, ReagentPlus^®, ≥99%

215619

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224227

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

248576

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Titanium(IV) oxide, anatase, powder, −325 mesh, ≥99% trace metals basis

637262

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

634662

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

646687

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Silicon, wafer (single side polished), <100>, N-type, contains no dopant, diam. × thickness 2 in. × 0.5 mm

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633097

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700347

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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

647764

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204757

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

204730

Sigma-Aldrich

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

647675

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Silicon, wafer (single side polished), <100>, P-type, contains boron as dopant, diam. × thickness 2 in. × 0.5 mm

677469

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343250

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647535

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Silicon, wafer (single side polished), <100>, N-type, contains no dopant, diam. × thickness 3 in. × 0.5 mm

647780

Sigma-Aldrich

Silicon, wafer (single side polished), <100>, N-type, contains phosphorus as dopant, diam. × thickness 2 in. × 0.5 mm

647802

Sigma-Aldrich

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635057

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647543

Sigma-Aldrich

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647705

Sigma-Aldrich

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647772

Sigma-Aldrich

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