Assessing the aggregation behaviour of iron oxide nanoparticles under relevant environmental conditions using a multi-method approach

WATER RESEARCH

卷:47

Article

Chekli, Laura^1,2  Phuntsho, Sherub¹  Roy, Maitreyee³  Lombi, Enzo⁴  Donner, Erica^2,4  Shon, Ho Kyong^1,2 

[1] Univ Technol Sydney, Sydney UTS, Sch Civil & Environm Engn, Sydney, NSW 2007, Australia

[2] CRC CARE, Salisbury, SA 5106, Australia

[3] Natl Measurement Inst Australia, Dept Ind Innovat Sci Res & Tertiary Educ, Lindfield, NSW 2070, Australia

[4] Univ S Australia, Ctr Environm Risk Assessment & Remediat, Adelaide, SA 5095, Australia

关键词: Iron oxide;    Nanoparticles;    Aggregation;    Flow field-flow fractionation;    DLVO theory;    Surface coating;   

DOI  :  10.1016/j.watres.2013.04.029

来源: Elsevier

【 摘 要 】

Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe(2)O(3)NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach. Under some soil conditions (i.e. pH 7, 10 mM NaCl and 2 mM CaCl2) and increasing particle concentration, Fe(2)O(3)NPs underwent extensive aggregation to form large aggregates (>1 mu m). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative green solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe(2)O(3)NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe(2)O(3)NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl2, however, even at low concentrations, induced the aggregation of DOM-coated Fe(2)O(3)NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment. (C) 2013 Elsevier Ltd. All rights reserved.

【 授权许可】

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