Transport of engineered nanoparticles in partially saturated sand columns

Yinon Yecheskel, Ishai Dror, Brian Berkowitz

Research output: Contribution to journalArticlepeer-review

Abstract

The vadose zone is a critical region controlling fate and transport of contaminants in soils and, ultimately, groundwater. It is therefore important to understand the behavior of engineered nanoparticles (ENPs) in this zone, as a potential group of emerging contaminants. Soil is a significant sink for ENPs; however, only a few studies have considered the fate and transport of ENPs in partially saturated systems, representative of the vadose zone. Here, transport behavior of three commonly used ENPs - gold (Au-NPs), silver (Ag-NPs) and zinc oxide (ZnO-NPs) - is investigated in partially saturated sand columns. High mobilities of Au-NPs and Ag-NPs under different water saturation levels and concentrations were observed. The presence of CaCl2 reduces Ag-NP mobility through chemical interactions, similar to behavior reported in saturated systems. Furthermore, transformation of Ag-NPs in the environment may influence their mobility; aging of Ag-NPs following sulfidation was investigated. The silver sulfide (Ag2S-NPs) remained stable in aqueous suspension, and mobile in the partially saturated sand column. In contrast, the positively-charged ZnO-NPs were completely immobilized in the sand column. Significantly, though, addition of humic acid (HA) to the ZnO-NP suspension reverses particle surface charge and thus increases their mobility. Moreover, remobilization of entrapped ZnO-NPs by HA was demonstrated.
Original languageEnglish
Pages (from-to)254-262
Number of pages9
JournalJournal of Hazardous Materials
Volume311
DOIs
StatePublished - 5 Jul 2016

All Science Journal Classification (ASJC) codes

  • Pollution
  • Waste Management and Disposal
  • Health, Toxicology and Mutagenesis
  • Environmental Engineering
  • Environmental Chemistry

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