Description: The forecasted increase in the manufacture and use of nanoparticles makes it likely that increasing human and environmental exposure will occur, and as a result, nanoparticles have come under scrutiny. In natural waters, nanoparticles have to be present in 'solubilized' form because otherwise they will aggregate and flocculate and are removed (e.g. during wastewater treatment) or are retained in soil or groundwater. Both mobility and bioavailability depend therefore on the state of solubilization. Carbon nanotubes (CNT) are an important group of novel nanoparticles. Pristine CNT are virtually indispersable in water and do not form stable suspensions. However, they can be solubilized by addition of polymers (e.g. proteins and polysaccharides), detergents or natural organic matter. In the first part of this project the solubilization of CNTs was studied by bringing them in contact with biopolymers and detergents in aqueous solution and measuring the formation of solubilized, non-aggregated nanoparticles. Solubilization and sedimentation was followed over time, as function of water composition and initial state of the CNT. Dry CNTs were increasingly solubilized with increasing shaking time, however, the amount remaining stable in suspension was less than 1Prozent of the added amount. Pre-dispersing CNT in detergents and addition to water resulted in higher solubilized concentrations. In waters containing humic and fulvic acids addition of pre-dispersed CNT resulted in stable suspensions of up to 60Prozent of the total CNT amount. Our results indicate that the environmental behavior of CNTs is strongly determined by the initial state of the CNT. It is the aim of the extension project to get an in-depth view into the processes affecting dispersion of CNT by conducting titration experiments which will enable us to get a detailed description of the surface reactions on the CNT. Acid-base titrations will be performed with various CNT in the presence of different compounds (cations, detergents, biopolymers) and the data will be modeled using a surface complexation approach. These additional data will allow us to relate the solubilization of the CNTs to their surface speciation and will enable us to develop a more predictive understanding of the processes affecting solubilization of CNT in natural waters.
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Origins: /Bund/UBA/UFORDAT
Tags: Tierhaltungsanlage ? Naturpolymer ? Anionisches Tensid ? Reinigungsmittel ? Polymer ? Abwasserbehandlung ? Suspension ? Umweltbelastung ? Kohlenstoff-Nanoröhren ? Gewässerzustand ? Bildung ? Abwasser ? Bewässerung ? Bioverfügbarkeit ? Daten ? Dispersion ? Exposition ? Mensch ? Protein ? Säure ? Grundwasser ? Wasser ? Nanopartikel ? Messung ? Fullerene ? Ballungsraum ? Sedimentation ? Standortbedingung ? Umwelt ? Gewässer ? Wasser ? Staat ? Verkehrsmobilität ? Nanomaterialien ? Boden ? HERSTELLUNG ? NATURNAH ? NEU ? OBERFLAECHE ? BESCHREIBUNG ? PROJEKT ? Dispergierung ? SICHT ? STARK ? Stall ? EINSATZ ? ERGEBNIS ? TEIL ? EXPERIMENT ? Titration ? UNTER ? FORMBLAETTER ? VERARBEITEN ? FUNKTION ? VERBINDUNG ? VERWANDT ? Vermehrung ? WICHTIG ? Kationen ? BETRAG ? Basen [chemisch] ? GEGENWART ? Konzentrat ? GRUPPE ? LAENDER ? LOESUNG ?
License: cc-by-nc-nd/4.0
Language: Englisch/English
Time ranges: 2010-07-01 - 2011-06-30
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