Heteroaggregation of titanium dioxide nanoparticles with model natural colloids under environmentally relevant conditions

Publikation: Beiträge in ZeitschriftenZeitschriftenaufsätzeForschungbegutachtet

Authors

  • Antonia Praetorius
  • Jérôme Labille
  • Martin Scheringer
  • Antoine Thill
  • Konrad Hungerbühler
  • Jean-Yves Bottero

The heteroaggregation of engineered nanoparticles (ENPs) with natural colloids (NCs), which are ubiquitous in natural surface waters, is a crucial process affecting the environmental transport and fate of ENPs. Attachment efficiencies for heteroaggregation, αhetero, are required as input parameters in environmental fate models to predict ENP concentrations and contribute to ENP risk assessment. Here, we present a novel method for determining αhetero values by using a combination of laser diffraction measurements and aggregation modeling based on the Smoluchowski equation. Titanium dioxide nanoparticles (TiO2 NPs, 15 nm) were used to demonstrate this new approach together with larger silicon dioxide particles (SiO2, 0.5 μm) representing NCs. Heteroaggregation experiments were performed at different environmentally relevant solution conditions. At pH 5 the TiO2 NPs and the SiO2 particles are of opposite charge, resulting in αhetero values close to 1. At pH 8, where all particles are negatively charged, αhetero was strongly affected by the solution conditions, with αhetero ranging from <0.001 at low ionic strength to 1 at conditions with high NaCl or CaCl2 concentrations. The presence of humic acid stabilized the system against heteroaggregation.

OriginalspracheEnglisch
ZeitschriftEnvironmental Science & Technology
Jahrgang48
Ausgabenummer18
Seiten (von - bis)10690-10698
Anzahl der Seiten9
ISSN0013-936X
DOIs
PublikationsstatusErschienen - 16.09.2014

DOI