10. Abstract. Provide a brief (one-page) description of the problem, methods, and objectives in the space provided at the NIWR site. Problem The widely application of nano materials (NMs) have highly increased the potential release of NMs to environment. As many metallic nanoparticles (NPs) have shown acute or chronic biotoxicity, a rapid analysis method is needed to monitor the NP occurrence in aqueous environment. The estimated NP concentration around sub g/L in aqueous environment often requires a pretreatment to concentrate NP for UV/VIS or fluorescent spectrometer analysis. For further optical spectrometer analysis, it is necessary to extract the NPs from environmental sample which contains a variety of dissolved organic matters, while retaining their nano size and shape. Methods Silver NPs, nano ZnO, and nano TiO2 will be used for extraction test because of their wide application and risk concern in the environment. Liquid- liquid extraction (LLE) and solid-phase extraction (SPE) will be evaluated in terms of NP transfer efficiency and effect. Two LLE methods will be used for NP extraction, including cloud point extraction by Surfactant Triton X-114, ionic liquid extraction by 1-butyl-3- methylimidazolium hexafluorophosphate ([C4MIM][PF6]) and cholin acetate. SPE will be done by trata C18-E cartridges. Different types of stabilizer will be added into the sample to avoid potential aggregation or precipitation. The surface binding changes of NPs will be monitored by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The potential size change will be evaluated by transmission electron microscopy (TEM). Concentrated NP solution will be quantified by UV/VIS or fluorescence spectrometer. Single particle inductively coupled plasma mass spectrometry (SP- ICP- MS) will be used to confirm the transfer efficiency of NPs. Dissolved organic matter (DOM) such as carbonates and humic acid may affect the NP transfer efficiency and finally positively or negatively contribute to the measured values of optical spectrometer. Optimized method to minimize their effect will be proposed. And a standard procedure will be summarized to get a final practical protocol. Objectives The objectives of this project include following: 1), to evaluate the NP transfer efficiency by LLE and SPE; and 2), to determine the effect of dissolved organic matter (humic acid, carbonate..etc), pH, and ionic strength on extraction efficiency of NPs. Finally, a comprehensive protocol will be proposed for rapid extraction and quantification of NPs in water or wastewater by UV/VIS or fluorescent spectrometer.
|Effective start/end date||3/1/13 → 2/28/14|
- DOI: US Geological Survey (USGS): $10,000.00