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Eawag: Quantitative description of colloids in acqueous systems. Empa: Emissionprocesses of nanoparticles at material-environment-interface. T.o.E.: Asym. Field Flow Fractionation coupling to LIBD + ICPMS

English title Eawag: Quantitative description of colloids in acqueous systems. Empa: Emissionprocesses of nanoparticles at material-environment-interface. T.o.E.: Asym. Field Flow Fractionation coupling to LIBD + ICPMS
Applicant Kägi Ralf
Number 117376
Funding scheme R'EQUIP
Research institution Swiss Federal Institute of Aquatic Science and Technology (EAWAG)
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Other disciplines of Environmental Sciences
Start/End 01.07.2007 - 30.06.2008
Approved amount 160'000.00
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Keywords (8)

Colloids; particles; engineered nanoparticles; emission process; material-environment interface; water; partice size distribution; particle number concentration

Lay Summary (English)

Lead
Lay summary
Aquatic particles in the submicron range (colloids) significantly influence environmental and biogeochemical processes. Engineered nanoparticles (<100nm) are already used in remediation technology (e.g. nanosized zerovalent iron) and the applications of engineered nanoparticles (e.g. nanosilver and nano-TiO2) are increasing. However, the behavior of the colloids or nanoparticles in general in the environment is not fully understood, yet, and a considerable lack of knowledge exists regarding the (unintended) release from materials into the environment and the fate of engineered nanoparticles in the environment. To understand the behavior of environmental colloids and engineered nanoparticles in the environment, their fundamental physical parameters such as size, number, bulk and surface chemistry need to be measured. This, in turn, requires the combination of a several analytical techniques. Natural colloidal systems are highly complex regarding size, morphology and chemistry of the individual components (particles). Moreover, the differentiation between engineered particles and natural colloids is challenging and requires additionally chemical characterization.
The research interests of Eawag are focused on the effects of colloids (including engineered nanoparticles) in the environment. The focus of Empa research is on the interaction of nanoparticle containing materials with the environment and the potential (unintended) release of engineered nanoparticles into the environment.
The complexity of natural colloidal systems requires a sufficient size fractionation of the colloids prior to its analysis. The most promising technique for a size fractionating is the asymmetric flow field flow fractionation (asymmetric flow FFF) device. Its high size resolution, minimum interaction with surfaces and relatively rapid separation makes this technique less prone to artifacts and far more appropriate for a size fractionation compared to standard techniques such as filtration and centrifugation. After the size separation particle can be analyzed with a suite of techniques, each one delivers information about one physical property of the colloid or the chemical composition. The strength of the system is the integration of different analytical techniques, which enables an almost simultaneous measurement of a series of physical parameters of the same colloids. In addition to commercially available detectors such as UV-, RI- and MALLS, a coupling of laser induced breakdown detection (LIBD, this technique is not commercially available) is planned to archive information on particle numbers. Further, an online coupling to a plasma mass spectrometry (ICP-MS) will enable the measurement of a size classified chemical composition. Different size fractions of the colloids can be collected for subsequent microscopic investigations using the fraction collector. The size fraction can be chosen based on the previously performed measurements from the online detectors, which offers the possibility to look more specifically for certain particles.
Direct link to Lay Summary Last update: 21.02.2013

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