Experimental and Numerical Investigations of Silver Nanoparticle Transport under Variable Flow and Ionic Strength in Soil

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Institutes & Expert groups

  • FZJ - Forschungszentrum Jülich GmbH
  • TU Berlin - Institute of Applied Geosciences - Hydrogeology Department

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DOI

Abstract

Unsaturated column experiments were conducted with an undisturbed loamy sand soil to investigate the influence of flow interruption (FI) and ionic strength (IS) on the transport and retention of surfactant-stabilized silver nanoparticles (AgNP) and the results were compared to those obtained under continuous flow conditions. AgNP concentrations for breakthrough curves (BTCs) and retention profiles (RPs) were analyzed by ICP-MS. Experimental results were simulated by the numerical code HP1 (Hydrus-PhreeqC) with the DLVO theory, extended colloid filtration theory and colloid release model. BTCs of AgNP showed a dramatic drop after FI compared to continuous flow conditions. Evaporation increased due to FI, resulting in increased electrical conductivity of the soil solution, which led to a totally reduced mobility of AgNP. A reduction of IS after FI enhanced AgNP mobility slightly. Here the strongly increased Al and Fe concentration in the effluent suggested that soil colloids facilitated the release of AgNP (cotransport). The numerical model reproduced the measured AgNP BTCs and indicated that attachment to the air−water interface (AWI) occurring during FI was the key process for AgNP retention.

Details

Original languageEnglish
Pages (from-to)2096-2104
Number of pages9
JournalEnvironmental Science & Technology
Volume51
Issue number4
DOIs
Publication statusPublished - 21 Feb 2017

Keywords

  • silver , nanoparticle, transport, flow, ionic , soil

ID: 2556281