Investigation of the behaviour of zero-valent iron nanoparticles and their interactions with Cd2+ in wastewater by single particle ICP-MS

Janja Vidmar; Primož Oprčkal; Radmila Milačič; Ana Mladenovič; Janez Ščančar

doi:10.1016/j.scitotenv.2018.04.081

Investigation of the behaviour of zero-valent iron nanoparticles and their interactions with Cd²⁺ in wastewater by single particle ICP-MS

Sci Total Environ. 2018 Sep 1:634:1259-1268. doi: 10.1016/j.scitotenv.2018.04.081. Epub 2018 Apr 18.

Authors

Janja Vidmar¹, Primož Oprčkal², Radmila Milačič¹, Ana Mladenovič³, Janez Ščančar⁴

Affiliations

¹ Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia.
² Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia; Slovenian National Building and Civil Engineering Institute, Dimičeva ulica 12, 1000 Ljubljana, Slovenia.
³ Slovenian National Building and Civil Engineering Institute, Dimičeva ulica 12, 1000 Ljubljana, Slovenia.
⁴ Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia. Electronic address: janez.scancar@ijs.si.

PMID: 29660878
DOI: 10.1016/j.scitotenv.2018.04.081

Abstract

Zero-valent iron nanoparticles (nZVI) exhibit great potential for the removal of metal contaminants from wastewater. After their use, there is a risk that nZVI will remain dispersed in remediated water and represent potential nano-threats to the environment. Therefore, the behaviour of nZVI after remediation must be explored. To accomplish this, we optimised a novel method using single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) for the sizing and quantification of nZVI in wastewater matrices. H₂ reaction gas was used in MS/MS mode for the sensitive and interference-free determination of low concentrations of nZVI with a low size limit of detection (36nm). This method was applied to study the influence of different iron (Fe) loads (0.1, 0.25, 0.5 and 1.0gL^-1) and water matrices (Milli-Q water, synthetic and effluent wastewater) on the behaviour of nZVI, their interactions with Cd²⁺ and the efficiency of Cd²⁺ removal. The aggregation and sedimentation of nZVI increased with settling time. Sedimentation was slower in effluent wastewater than in Milli-Q water or synthetic wastewater. Consequently, Cd²⁺ was more efficiently (86%) removed from effluent wastewater than from synthetic wastewater (73%), while its removal from Milli-Q water was inefficient (19%). The trace amounts of Cd²⁺ that remained in the remediated water were either dissolved or sorbed to residual nZVI. The results of the nanoremediation of effluent wastewater with varying Fe loads showed that sedimentation was faster at higher initial concentrations of nZVI. After seven days of settling, low concentrations of Fe remained in the effluent wastewater at Fe loads of 0.5gL^-1 or higher, which could indicate that the use of nZVI in nanoremediation under the described conditions may not represent an environmental nano-threat. However, further studies are needed to assess the ecotoxicological impact of Fe-related NPs used for the nanoremediation of wastewaters.

Keywords: Cd(2+) removal; Nanoremediation; Single particle ICP-MS; Zero-valent iron nanoparticles.