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Determination of tire wear markers in soil samples and their distribution in a roadside soil

Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0-2, 2-5, 5-10, and 10-20 cm. Four fine fractions, 1 000-500, 500-100, 100-50, and <50 mikrom, were analyzed. TW contents based on SBR ranged from 155 to 15 898 mg kg-1. TW contents based on zinc were between 413 and 44 812 mg kg-1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance. The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation. © 2022 The Authors

Analysis of polyethylene microplastics in environmental samples, using a thermal decomposition method

Small polymer particles with a diameter of less than 5 mm called microplastics find their way into the environment from polymer debris and industrial production. Therefore a method is needed to identify and quantify microplastics in various environmental samples to generate reliable concentration values. Such concentration values, i.e. quantitative results, are necessary for an assessment of microplastic in environmental media. This was achieved by thermal extraction in thermogravimetric analysis (TGA), connected to a solid-phase adsorber. These adsorbers were subsequently analysed by thermal desorption gas chromatography mass spectrometry (TDS-GC-MS). In comparison to other chromatographic methods, like pyrolyse gas chromatography mass spectrometry (Py-GC-MS), the relatively high sample masses in TGA (about 200 times higher than used in Py-GC-MS) analysed here enable the measurement of complex matrices that are not homogenous on a small scale. Through the characteristic decomposition products known for every kind of polymer it is possible to identify and even to quantify polymer particles in various matrices. Polyethylene (PE), one of the most important representatives for microplastics, was chosen as an example for identification and quantification.Quelle: http://www.sciencedirect.com

Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine

The adsorption of organic micropollutants onto activated carbon is a favourable solution for the treatment of drinking water and wastewater. However, these adsorption processes are not sufficiently understood to allow for the appropriate prediction of removal processes. In this study, thermogravimetric analysis, alongside evolved gas analysis, is proposed for the characterisation of micropollutants adsorbed on activated carbon. Varying amounts of carbamazepine were adsorbed onto three different activated carbons, which were subsequently dried, and their thermal decomposition mechanisms examined. The discovery of 55 different pyrolysis products allowed differentiations to be made between specific adsorption sites and conditions. However, the same adsorption mechanisms were found for all samples, which were enhanced by inorganic constituents and oxygen containing surface groups. Furthermore, increasing the loadings led to the evolution of more hydrated decomposition products, whilst parts of the carbamazepine molecules were also integrated into the carbon structure. It was also found that the chemical composition, especially the degree of dehydration of the activated carbon, plays an important role in the adsorption of carbamazepine. Hence, it is thought that the adsorption sites may have a higher adsorption energy for specific adsorbates, when the activated carbon can then potentially increase its degree of graphitisation. © The Author(s) 2020

The Formation of Peroxyacetyl Nitrate (PAN) in Summer Smog

Das Projekt "The Formation of Peroxyacetyl Nitrate (PAN) in Summer Smog" wird vom Umweltbundesamt gefördert und von Eidgenössische Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz durchgeführt. Peroxyacetyl nitrate (PAN) is an important component of summer smog. It can cause eye irritation and plant damage. PAN is also a temporary reservoir for reactive intermediates involved in summer smog formation. Therefore it is essential to know the kinetics and mechanism of its formation and destruction for inclusion in models of atmospheric chemistry. PAN is formed as a secondary product following the OH radical initiated photo-oxidation of acetaldehyde, which leads to the generation of peroxyacetyl radicals. Peroxyacetyl radicals may either react with NO2 to generate PAN or with NO to form radical products and CO2. The aims of this project are: (i) to determine the branching ratio between the two reactions, (ii) to determine the rate and mechanism of the thermal decomposition of PAN analogues.

Der Verbleib von Carbonylradikalen (R-C=O) in der Atmosphaere

Das Projekt "Der Verbleib von Carbonylradikalen (R-C=O) in der Atmosphaere" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Physikalische Chemie durchgeführt. In addition to peroxy and alkoxy radicals, carbonyl (ie substituted acetyl) radicals (R-C=O) are important short-lived radical intermediates in the atmospheric degradation of volatile organic compounds. In order to supply atmospheric modellers with the necessary input data, rate parameters for reactions of these radicals are needed. The principal reaction pathways of carbonyl radicals are either thermal decomposition or addition of O2, leading to different product distributions and thus affecting the amount of ozone formation. In this project, state-of-the-art experimental methods are applied to quantify the branching ratio of these two pathways for a number of atmospherically important carbonyl radicals. Since thermal decomposition of R-CO generally exhibits much stronger temperature dependence as compared to O2 addition, the branching ratio of these pathways is also strongly temperature dependent. For this reason, variable temperature is an important feature of the planned experiments. The addition pathway leads to substituted acetylperoxy radicals. For a small number of these radicals, reaction rate constants for their reactions with NO, NO2, and HO2 will also be determined. The effect on atmospheric chemistry of the rate parameters coming out of this project will be tested by sophisticated box model calculations. The most important radical reactions will then be implemented into a new regional atmospheric chemistry model (RACM) in order to give an account of the influence of these R-CO radicals on atmospheric chemistry. It is expected that inclusion of the experimental data from this project into atmospheric chemistry models will considerably improve the predictions about radical balances and ozone formation in the troposphere which form the basis for future ozone control strategies.

Nutzung von Lignin als Rohstoff fuer Chemieprodukte

Das Projekt "Nutzung von Lignin als Rohstoff fuer Chemieprodukte" wird vom Umweltbundesamt gefördert und von RÜTGERS Chemicals AG, Duisburg durchgeführt. Screening zur Nutzung von Lignin als Rohstoff fuer Chemieprodukte in folgender Hinsicht: a. Thermolyse von Organosolv - sowie Hydrolyselignin bei Anwesenheit von 9.10-Dihydroanthracen resp. Steinkohlenteerfraktionen (Steinkohlenteerpech, aromatische Oele) bei 300 bis 400 Grad Celsius. Es entstehen Phenole und Phenolhomologe in einer Gesamtausbeute bis 18 Gew.-Prozent bezogen auf eingesetztes Lignin sowie ein thermoplastischer Rueckstand, der aus Lignin-Oligomeren (durch Depolymerisation) von Lignin) und aromatischen Kohlenwasserstoffen (aus der eingesetzten Teerfraktion) besteht. b. Verwendung von Lignin in Phenol-Formaldehyd-Harzen. In Harzen fuer die Spanplattenherstellung lassen sich bis etwa 10 v.H. des Harzes durch Organosolv-Lignin ersetzen, ohne dass die Normkenndaten fuer die hoechstwertigen Spanplatten unterschritten werden. Bei der Herstellung von Phenol-Formaldehyd-Giessereiharzen bietet die Verwendung von Organosolv-Lignin keine Vorteile.

Recycling von Bestandteilen von Getraenkekartons

Das Projekt "Recycling von Bestandteilen von Getraenkekartons" wird vom Umweltbundesamt gefördert und von Strepp Papierfabrik Hochkoppelmühle durchgeführt. The objective of the project is to make the high grade cellulose from beverage cartons available to the paper industry and to avoid remains consisting of Al-PE composites. These remains will be used to produce thermal energy from the polyethylene in a pyrolytic process and aluminium will be separated. Up to now the residual laminate of aluminium (Al) and polyethylene (PE) produced from the recycling of composite packagings has not been able to be economically processed. It is generally dumped at high costs. An economical, environmentally compatible alternative is thermolysis of PE since the present processing capacities for recycling are greatly inadequate. Moreover, the quality of the plastic falls in every recycling process (downcycling). A demonstration plant with a throughput of 36000 tpa composite material is planned. The paper industry could hereby be supplied with approx 25000 tpa of high-quality cellulose. At the same time around 1500 tpa of aluminium would be produced and could be used in Al-processing industries. Around 7500 tpa of polyethylene can be put to direct thermal use, thus easing the burden on the energy balance during paper manufacture. The cooperation with a Spanish partner is desirable since the problems there are similar to those encountered here and an international transport of waste could thus be prevented.

Zn-recovery from steel making dusts - Kinetics and mechanism of thermal zinc-ferrite phase decomposition

Das Projekt "Zn-recovery from steel making dusts - Kinetics and mechanism of thermal zinc-ferrite phase decomposition" wird vom Umweltbundesamt gefördert und von RWTH Aachen University, Institut und Lehrstuhl für metallurgische Prozesstechnik und Metallrecycling durchgeführt. This project focuses on a pyrometallurgical treatment of iron-zinc concentrate in order to study the mechanism and kinetics of thermal zinc ferrite phase decomposition. Combination of Pyrometallurgical and hydrometallurgical treatment of FeZn-concentrate was used. The degree and kinetic of thermal decomposition of zinc ferrite was considered by TGA and DTA Analysis. The thermal decomposition of zinc ferrite was investigated in rotary kiln and tubular furnace. Leaching of decomposed solid residue was performed under atmospheric and high pressure conditions.

Teilvorhaben 2: Reduktive Thermolyse von Zuckern

Das Projekt "Teilvorhaben 2: Reduktive Thermolyse von Zuckern" wird vom Umweltbundesamt gefördert und von Fraunhofer-Institut für Chemische Technologie durchgeführt. Durch reduktive Hydrothermolyse sollen einfache Zucker wie Glucose, Fructose oder Xylose mit einem hohen Anteil chemisch nahezu äquivalenter Hydroxylgruppen in C2-, C3-, C4-, C5- und C6-Polyole mit dem Ziel umgewandelt werden, eine neue Rohstoffbasis für Polyole zur Herstellung von Kunststoffen wie z. B. Polyestern oder Polyurethanen bereitzustellen. Die ausgewählten Zucker zeichnen sich durch eine hohe Anzahl von Hydroxylgruppen neben einer Aldehyd- bzw. Ketogruppe aus. Ziel ist es nun, die Struktur des Kohlenstoffgerüsts und die Hydroxylgruppen zu erhalten und die Aldehyd- bzw. Ketogruppe zu reduzieren. Da bei erhöhten Temperaturen gearbeitet wird, treten wegen des zunehmenden Acidifizierungspotentials des Wassers Kondensationsreaktionen zu Furanen oder Spaltungsreaktionen zu Bruchstücken auf. Durch die Gegenwart des zuvor aus Kohlenmonoxid und Wasser in situ erzeugten Wasserstoffs wird eine Oxidation der gebildeten Reaktionsprodukte verhindert und gleichzeitig eine Reduktion der Carbonylfunktion angestrebt.

Ermittlung optimaler Betriebsparameter fuer den Thermolyseeinsatz zur Aufbereitung von Bioschlaemmen aus der Nahrungsmittel- und Brauereiproduktion

Das Projekt "Ermittlung optimaler Betriebsparameter fuer den Thermolyseeinsatz zur Aufbereitung von Bioschlaemmen aus der Nahrungsmittel- und Brauereiproduktion" wird vom Umweltbundesamt gefördert und von Technische Hochschule Aachen, Forschungsinstitut für Wassertechnologie durchgeführt. Vielerorts besteht das Problem der Klaerschlammbeseitigung, die meistens sehr kostspielig ist. Es ist aber bekannt, dass in Klaerschlamm Eiweiss in Form von Einzellerprotein (SCP) enthalten ist. Daher sollte untersucht werden, wie weit Klaerschlamm als Eiweissquelle fuer Viehfutter genutzt werden kann und wie er am guenstigsten aufbereitet wird. Als wichtigste Voraussetzung ist zu nennen, dass die Gehalte an toxischen Stoffen unter unbedenklichen Maximalwerten liegen muessen. Daher duerfen lediglich Bioschlaemme aus Klaeranlagen bestimmter Industrien wie z.B. Lebensmittel- und Getraenkeindustrie genutzt werden. Weiterhin muss der Bioschlamm so aufgeschlossen werden, dass das in den Mikroorganismen enthaltene und von einer unverdaulichen Zellwand umgebene Protein in eine verdauliche Form gebracht wird. Um dies zu erreichen, muss die Zellwand zerstoert werden. Dies kann z.B. chemisch oder thermisch erfolgen. Die Versuche wurden auf einem Zweiwalzen-Sumpftrockner durchgefuehrt. Die Trocknungstemperatur lag zwischen 120 und 140 Grad Celsius, die Spaltweite zwischen 0,1 und 0,3 mm, die Trocknungsdauer zwischen 10 und 30 Sec. Der Proteingehalt der verschiedenen Schlaemme war zwischen 20 und 30 Prozent und ist daher durchaus positiv zu bewerten.

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