Year Established: 2013 Start Date: 2013-03-01 End Date: 2014-02-28
Total Federal Funds: $10,000 Total Non-Federal Funds: $20,000
Principal Investigators: Paul Westerhoff, Yu Yang
Abstract: Problem: Increasing use of engineered nanomaterials (NMs) in industry, commerce, food, pharmaceutical, residential and agricultural applications have begun and likely will lead to their release to the environment. We have published on metallic and carbonaceous nanomaterial occurrence in food, personal care products, fabrics and wastewater effluents & biosolids. Nanoparticles are one important category of NMs, and are operationally defined as having at least one dimension less than 100 nm. Metallic NPs including those based upon silver, zinc, titanium exhibit acute and chronic toxicity, albeit the literature has not developed nomenclature and consistent dosemetrics for these endpoints nor do they document single mechanisms of toxicity. Managing the risk from engineering NPs requires exposure data to accompany toxicity data, and our group has been at the forefront of method develop with funding from the USEPA, NIEHS, WERF and the semiconductor industry. Like other trace pollutants, extraction and separation methodologies from complex aqueous matrices (wastewater, surface water, etc.) allow increased sensitivity and quantification. For metallic NPs extraction methods would facilitate differentiation of ionic versus nano or particulate forms. Approach: We have evaluated solvent and solid phase extraction efficiency of buckyball fullerenes (nC60), so here we propose to focus on metallic NPs. Well characterized 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. This will be compared against our published data on using centrifugal ultrafiltration. Experiments will assess recovery efficiency as a function of initial concentration and water matrix conditions (ultrapure water, Colorado River water, raw and treated wastewater). Objectives: The objective of this research is to compare recovery efficiencies of several metallic nanoparticles by various LLE and SPE methodologies. In the shorter-term, extraction will enhance our ability to separate NPs from complex matrices, aiding in more detailed characterization (microscopy). In the longer-term we believe that our straight-forward extraction procedures could be coupled with in-expensive photonic based detection (UV/VIS or fluorescence) which leverage the surface plasmon properties of metallic NPs to have robust methods to answer a question are nanoparticles present in my water, or coupled with other methodologies we have developed around single particle ICP-MS to assess size and number of particles.