Stability and aggregation of metal oxide nanoparticles in natural aqueous matrices

Arturo A. Keller, Hongtao Wang, Dongxu Zhou, Hunter S. Lenihan, Gary Cherr, Bradley J. Cardinale, Robert Miller, J. I. Zhaoxia

Research output: Contribution to journalArticlepeer-review

1175 Scopus citations


There is a pressing need for information on the mobility of nanoparticles in the complex aqueous matrices found in realistic environmental conditions. We dispersed three different metal oxide nanoparticles (TiO2, ZnO and CeO2) in samples taken from eight different aqueous media associated with seawater, lagoon, river, and groundwater, and measured their electrophoretic mobility, state of aggregation, and rate of sedimentation. The electrophoretic mobility of the particles in a given aqueous media was dominated by the presence of natural organic matter (NOM) and ionic strength, and independent of pH. NOM adsorbed onto these nanoparticles significantly reduces their aggregation, stabilizing them under many conditions. The transition from reaction to diffusion limited aggregation occurs at an electrophoretic mobility from around -2 to -0.8 m s-1 V-1 cm. These results are key for designing and interpreting nanoparticle ecotoxicity studies in various environmental conditions.

Original languageEnglish (US)
Pages (from-to)1962-1967
Number of pages6
JournalEnvironmental Science and Technology
Issue number6
StatePublished - Mar 15 2010

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Environmental Chemistry


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