Lifetime and dissolution kinetics of zinc oxide nanoparticles in aqueous media

Ning Wang, Tiezheng Tong, Minwei Xie, Jean-Francois Gaillard

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

We have assessed the persistence and lifetime of ZnO nanoparticles (ZnO-NPs) by performing dissolution experiments in three different aqueous media. These experiments were performed at ZnO-NP concentration levels close to the solubility of zincite (∼8 μM or 650 μg l -1 of ZnO) - a concentration that is orders of magnitude higher than current estimated relevant environmental concentrations. The kinetics were followed by voltammetry, while maintaining the pH at about 7.5 using a CO 2 /N 2 gas mixture to remove di-oxygen interference. Our results show that, under these conditions, ZnO-NPs readily dissolve with a lifetime expectancy that does not exceed 90 min. Water chemistry, especially the presence of dissolved organic matter (DOM), plays an important role in ZnO-NP dissolution. Dissolution rates significantly increase in the presence of strong chelating agents, EDTA and L-cysteine, while the addition of polymeric DOM, such as sodium alginate, has the opposite effect. Our results suggest that ZnO-NPs are unlikely to persist in natural aqueous media and that the toxicity should be primarily related to the released Zn 2+ ions rather than effects commonly associated to the presence of nanoparticles.

Original languageEnglish (US)
Article number324001
JournalNanotechnology
Volume27
Issue number32
DOIs
StatePublished - Jun 27 2016

Keywords

  • ZnO-NPs
  • dissolution kinetics
  • lifetime
  • organic ligands
  • voltammetry

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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