Dieselruß: Mikrostruktur und Oxidationskinetik

The engine internal emission reduction of commercial vehicles has been very im-pressive during the last ten years. The mass related reduction of the soot emission is a result of the reduced number of particles also with regard to those <50nm. The microstructures in atomic scale and the bonding states (electronic structures) of soot particles emitted by advanced commercial vehicles engines will be elucidated by means of TEM, HRTEM and EELS. Core-shelled spheroidal primary particles are found as described in the literature, but more primary particles do not exhibit a defined structure. The high-resolution imaging reveals irregular shaped primary particles with a deformed fullerenoid structure (size between 10 and 20nm) and fullerene-like clusters or molecules on the surface of the primary particles [Sum03]. XPS, FTIR (DRIFTS) spectroscopy are applied to reveal the functional groups on surface and the bulk composition of the soot particles. The surface of the soot is highly covered with oxygen containing functional groups Giant PAHs, e.g. hexabenzocoronene, are volatilized to form an aerosol containing GPAH clusters similar in size like primary soot particles. This aerosol is used to study the reactivity of a chemically well defined model soot. Models for BSU stacks (size~2nm) are detected by MALDI-TOF-MS. The largest cluster found is (C96H30)6 with the mass 7098 u. The microstructures of soot particles are related to the chemical reactivity against the oxidizing agent nitrogen dioxide, NO2 by kinetic measurements. The obtained knowl-edge will be applied in the practice for minimizing the soot particle emission of diesel en-gines and for increasing the activity of exhaust aftertreatment with PM-KATâ and GD-KAT systems. The investigation of the formation and the properties of diesel soot of advanced commercial engines is just at the beginning. We expect that the chemical properties of the surface and the microstructure of soot emitted from advanced diesel engines will re-define toxicity (threshold value of secondary genotoxicity) and relevance of physical measurement methods

Microplastic in the water cycle : sampling, sample preparation, analyses, occurrence and assessment

Gedruckt erschienen im Universitätsverlag der TU Berlin, ISBN 978-3-7983-3162-4Das interdisziplinäre Forschungsprojekt MiWa widmete sich grundlegenden Fragestellungen zur Analytik und Wirkung von Mikroplastik-Partikeln im Wasserkreislauf. Es wurden Methoden der Umweltprobennahme, der Probenaufbereitung und verschiedene Detektionsverfahren zur Charakterisierung und Quantifizierung von Mikroplastik intensiv untersucht, miteinander verglichen und weiterentwickelt. Öko- und humantoxikologische Untersuchungen dienten dem Zweck, die potenziell von Mikroplastik ausgehende Gefährdung für die aquatische Umwelt und den Menschen zu analysieren und zu bewerten. Eine Harmonisierung und Standardisierung von Methoden der Probennahme, Probenaufbereitung und Mikroplastik-Detektion sind trotz der erheblichen Fortschritte derzeit nur teilweise möglich. Die ökotoxikologischen Studien zeigen zwar die Aufnahme von Mikroplastik-Partikeln durch einige Organismen, jedoch konnte bisher keine schädigende Wirkung nachgewiesen werden. Dabei wurden für eine Auswahl aquatischer Modellspezies sowohl Szenarien direkter als auch indirekter Exposition innerhalb einer Nahrungskette betrachtet. Interaktionen mit menschlichen Modellzellen wurden bislang nur bei Mikroplastik-Partikeln mit Größen weit unterhalb von 1 µm (also Nanoplastik) beobachtet. Eine umfassende Bewertung ist bislang nicht möglich.The interdisciplinary research project MiWa focused on principle knowledge gaps of analytical detection and effects of microplastic in fresh water cycles. Methods for environmental sampling, sample preparation and different analytical identification and quantification were intensively investigated, compared and further developed. Toxicological studies were conducted to assess potential risks of microplastic particles towards the environment and human health. Harmonization and standardization are still only partially possible despite various improvements. The eco-toxicological experiments confirmed the intake of microplastic particles by different organisms but no hazardous effects could be found. Both direct ingestions and indirect exposition within food webs were tested. Interactions with exemplary human cells were only observed for particle sizes far below 1 µm (thus nanoplastic). An assessment is currently only possible to a limited extent.BMBF, 02WRS1378, Mikroplastik im Wasserkreislauf (MiWa