Issue 1, 2019

Heteroaggregation and dissolution of silver nanoparticles by iron oxide colloids under environmentally relevant conditions

Abstract

The ubiquity and abundance of iron oxides in the subsurface highlight their important roles in influencing the fate and transport of engineered silver nanoparticles (AgNPs). In this study, the adsorption behaviors of AgNPs on two naturally occurring iron oxides, goethite and hematite, were investigated under environmentally relevant conditions. The maximum surface coverage of AgNPs on iron oxides ranged between 0.014 and 0.326 mg m−2 depending on the investigated ionic strength and pH. The particle interactions (AgNPs–AgNPs and AgNPs–goethite/hematite) were probed by aggregation kinetics measurements using time-resolved dynamic light scattering and Derjaguin–Landau–Verwey–Overbeek theory calculations, which confirmed the predominant role of heteroaggregation in AgNP adsorption onto iron oxides. Multiple state-of-the-art characterization studies using X-ray absorption spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy, and X-ray diffraction substantiate the dominant electrostatic attractions between AgNPs and iron oxides. Moreover, AgNP dissolution was reduced in the presence of iron oxides. Goethite was more effective than hematite in retaining AgNPs (5.1 to 16.3-fold higher) and inhibiting AgNP dissolution (1.2 to 5.7-fold lower), due to their surface charge differences. Altogether, our findings provide compelling evidence of the dominant role played by electrostatic attractions in AgNP adsorption by iron oxides and of inhibition of AgNP dissolution during the heteroaggregation process, which has important implications for better evaluating the potential environmental impacts and risks of AgNPs in the iron oxide-rich subsurface.

Graphical abstract: Heteroaggregation and dissolution of silver nanoparticles by iron oxide colloids under environmentally relevant conditions

Supplementary files

Article information

Article type
Paper
Submitted
23 May 2018
Accepted
15 Nov 2018
First published
16 Nov 2018

Environ. Sci.: Nano, 2019,6, 195-206

Heteroaggregation and dissolution of silver nanoparticles by iron oxide colloids under environmentally relevant conditions

R. Wang, F. Dang, C. Liu, D. Wang, P. Cui, H. Yan and D. Zhou, Environ. Sci.: Nano, 2019, 6, 195 DOI: 10.1039/C8EN00543E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements