Authors: S. Choi, J. Eichhorn, M. Johnston, C.P. Huang
Affilation: University of Delaware, United States
Pages: 171 - 174
Keywords: nanoparticle, detection, ICP-OES
The objective of this research was to develop a method reliable for the detection and quantification of engineered nanoparticles in municipal wastewater treatment systems. Wastewater and sludge samples were sampled from four regional municipal wastewater treatment plants. The samples were dialyzed first to remove the soluble salts, many of them were derived from the solubilized ENPs selves, from the wastewater. The salt-free samples were then treated with an advanced chemical oxidation process of thermal hydrogen peroxide, to remove the organic and biological constituents. The salt-free and organic-free suspension was acid digested and treated with high energy ultrasound probe to obtain the free ENPs. The free ENPs so obtained were characterized for crystal structure and chemical composition using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Wet chemistry methods were also used to quantify the amounts of ENPs present in the wastewater or sludge samples using inductively coupled plasma methods (ICP-OES, MS). Results showed that concentration of metallic ENPs such as titanium oxide, silicon dioxide, iron oxide and ferric oxide up to a level of 100 µg/L was detected.