4 Material und Umwelt
Filtern
Dokumenttyp
- Vortrag (75)
Referierte Publikation
- nein (75) (entfernen)
Schlagworte
- Nano (18)
- Nanomaterial (10)
- OECD (10)
- Nanopartikel (6)
- Emission (5)
- BEMMA (4)
- Bauprodukte (4)
- Bundesoberbehörden (4)
- EN 16516 (4)
- Prüfrichtlinie (4)
Organisationseinheit der BAM
- 4.2 Material-Mikrobiom Wechselwirkungen (75) (entfernen)
Eingeladener Vortrag
- nein (75) (entfernen)
Mit dem Fokus auf eine saubere Innenraumluft wird darauf eingegangen, welche Emissionen aus Materialien und Produkten es gibt und wie sie nach Art und Flüchtigkeit definiert sind und wie sie gemessen werden. Im weiteren wird dargestellt, was und wie viel aus Materialien und Produkten emittieren kann und wie die Emissionen zu bewerten sind. Hierbei wird auch auf besonders emissionsarme Materialien und Produkte eingegangen.
Two new approaches towards an emission reference material for use in quality assurance measures for materials emissions testing were developed and intensively tested. The overall goal was to obtain solid materials with homogenous and reproducible (S)VOC release. Since the application in inter-laboratory comparisons is aimed at, it should furthermore be long-term stable to ensure safe shipment to the customer without sustaining compound losses. In the first approach, thermoplastic polyurethane (TPU) was impregnated with the VOC texanol under high-pressure with liquid CO2 as solvent. In the second, styrene (VOC) and the SVOC 2,6-diisopropylnaphthalene (DIPN) were spiked into vacuum grease (VG) and a mixture of paraf-fin/squalane (P/S). For the prediction of the emission rates a finite element model (FEM) was developed for the VG and P/S type materials. All requirements for reference materials were fulfilled, whereas the TPU samples need to be aged for about 10 days until repeatable and reproducible emission rates were obtained.
The properties of nanomaterials are influenced not only by their chemical composition but also by physical properties (such as size, geometry and crystal structure). For the reliable determination and assessment of behaviour and effects of nanomaterials as well as for the determination of the exposure of humans and environment a comprehensive physical-chemical characterization of nanomaterials is essential. This is an important prerequisite to identify them as nanomaterials and to interpret and compare test results and - in future – to forecast interaction and effects of nanomaterials.
In 2006, the OECD launched a sponsorship program for the testing of nanomaterials in which 11 nanomaterials were thoroughly investigated using a variety of methods. The aim of the project was, among other things, to find out where problems occur and where there are gaps in the measurement and test procedures and where are changes required. An important outcome of the sponsorship program was the finding that the OECD Test Guidelines should in several cases be extended to the specific needs in testing of nanomaterials. The existing standardized test methods of the OECD for physical-chemical characterization have not been developed for nanomaterials in particular. A high demand for an extension of the test guidelines was identified. Germany complied with the OECD's request in 2017 and has agreed to extend the “Test Guideline on Particle Size Distribution / Fiber Length and Diameter Distributions Test Guideline” for Manufactured Nanomaterials (MN). UBA commissioned BAM and BAuA with the preparation of the Test Guideline. The aim of the project is the development of a harmonized test protocol for a valid and reproducible determination of particle size and size distribution which is one of the most relevant physical-chemical properties for MNs.
Different measuring methods provide different results for the size distribution of the particles. This is caused by the different measuring principles of the methods. Each method measures a specific parameter that ultimately determines particle size. First, the measured quantity differs for each method (Scattered light intensity, 2D image / projection, electric mobility, etc.). Second, the calculated diameters of the MN may differ (Feret Diameter, Area Projection, Mobility Diameter, Aerodynamic Diameter, Hydrodynamic Diameter). Third, a measuring method provides a size distribution which is measured either mass-based, surface-based or number-based. A conversion between the results requires additional parameters and thus possibly increases the measurement error.
In addition to the technical differences, the individual parameters are strongly influenced by the structure and material of the nanoparticles. For example, a surface functionalization can lead to very different results in the size distribution. The suitability of measurement methods differs with the material of the MN. As a result, two very different results can be measured for the particle size distribution using two different methods, which are nevertheless both correct. Several large projects in recent years therefore concluded that nanomaterials should be characterized by at least two complementary method. Imaging techniques are regarded as one of these methods for the characterization, the complementary methods are supposed to be statistical methods.
The different results for the size distribution of nanomaterials become problematic for the registration of new MN. A comparable and reproducible size distribution is a prerequisite for a standardized registration. In the future, the particle size distribution in the EU will also decide on the classification of a substance as a nanomaterial or as a non-nanomaterial. Especially in borderline cases, a standardized and comparable measurement methodology is therefore essential.
Today glass is broadly used in modern architecture. For applications indoor it is possible to produce decor glass by using enamel colors and glass painting techniques without any problems. However, this is more limited for applications outdoor. Humidity and environmental pollution attack the surface of the coating and damage it strongly. There are only few colors on the market which are resistant towards acids and bases until now. Additionally, most of those colors are opaque. In order to extend the color palette, chemically resistant colored glasses are being developed which are transparent, relatively low melting and intensively toned even in thin coat thickness. To achieve such ambitious aim, many parameters have to match which act in complex manner. Metal oxides were used to color the glasses. A lead-free glass composition was developed to avoid an exposition of heavy metals to the environment. The glasses were characterized, in particular in terms of their thermal properties, their crystallization and corrosion behavior as well as their chemical and environmental durability. Different practical applications will be shown.
Fluorometric sensing is a versatile approach for trace analysis outside of the laboratory, requiring suitable sensor materials and their integration into sensing devices. The versatility of fluorophores as probes, especially in terms of the possibility to tailor their optical as well as their recognition properties by synthetic modifications in a wide range, renders them as superior active component for the preparation of optical sensing devices. Recent works at BAM in this field include, for example, the detection of nerve gas agents, illustrating impressively the aforementioned benefits of fluorophores in optical sensing applications.
In the interdisciplinary project presented here, we target hazardous gases such as ammonia, benzene, and hydrogen sulfide, next to others, which pose a major threat to human health and environmental safety and for which the availability of a sensitive and reliable detection method is highly desirable. The dyes presented follow a “turn-on” fluorescence schematic, which allows for the selective and sensitive detection of the respective gaseous analyte. The immobilization of the probe in polymeric matrices is then the next step toward the fabrication of a prototype device for molecular sensing. Further steps in the project include the assembly of instruments for test-atmosphere generation, the referencing of the sensor system, development and implementation of an optical setup, and the testing of the prototype device under laboratory conditions and in the field.
In this presentation, we give an overview over the recent developments on this topic in our groups. Highlights are hydrogen sulfide sensitive, BODIPY based transition metal complexes, which allow for a sensitive as well as selective detection of the toxic gas. In addition, we present a novel class of highly substituted BODIPY derivatives – pocket-BODIPYs – which are of a synthetically high versatility and can readily be modified to create pockets in the periphery of the molecule of defined geometries. This is illustrated on the successful encapsulation of benzene by a pocket-BODIPY derivative, confirmed by X-ray crystallographic analysis as well as by further spectroscopic and analytical methods.
Ammoniakemissionen in die Umwelt erfolgen insbesondere durch die Landwirtschaft (93,6 %), aber auch durch Verbrennungsprozesse in der die Abfallwirtschaft (2,3 %) und den Straßenverkehr (1,8 %). Dieser Stoff ist selbst in geringen Konzentrationen nicht nur eine Geruchsbelästigung, sondern auch eine Substanz mit ökologischer und klimatischer Relevanz.
Die Bestimmung von Ammoniak in relevanten Konzentrationen von kleiner 25 μg m-3 erfolgt im Allgemeinen über NH4+ als Analyten, spektralfotometrisch oder mit der Ionenchromatographie nach Überführung in die flüssige Phase. Wegen der niedrigen Konzentrationen an Ammoniak in der Außenluft wird meist eine gesammelte Probe verwendet oder die Bestimmung erfolgt nach einer aktiven, anreichernden Probenahme.
Die eigenen Arbeiten sollen dazu beitragen, die Ammoniak-Bestimmung in der Außenluft präziser, sowie schneller und kostengünstiger zu machen.
Die BAM prüfte daher kommerzielle elektrochemische und Metalloxid-basierte Sensoren, die für diesen Konzentrationsbereich aber nur bedingt geeignet sind. Deshalb wurden alternativ eigene Entwicklungen zum Nachweis von Ammoniak im Spurenbereich aufgenommen, wobei der Analyt über die Änderung der Fluoreszenz eines BODIPY-Farbstoffs bei 550 nm mittels eines portablen Fluoreszenz-Sensors direkt aus der Gasphase gemessen wird.
Zur Kalibrierung von Ammoniak-Sensoren und -Messgeräten steht ein stationäres System basierend auf der Mischung von zertifizierten Prüfgasen aus Druckflaschen mit kalibrierten Massendurchfluss-regler (MFC) zur Verfügung. Darüber hinaus erfolgt eine chemische Analyse der verwendeten Gasgemische mittels eines Massenspektrometers.
Für die Kalibrierung und Prüfung von Sensoren und Messgeräten vor Ort wurde ein mobiles Prüfsystem entwickelt. Die Generierung von Ammoniak-haltigen Gasen im Spurenbereich von 0,5 nmol/mol bis 500 nmol/mol erfolgt durch das Permeationsverfahren nach ISO 6145-10.
Für die Realisierung der Rückführbarkeit der Ammoniakbestimmung werden von den Nationalen Metrologischen Instituten sowie designierten Instituten Standards bereitgestellt und auch weiterentwickelt. Die primären metrologischen Standards beruhen auf SI-Einheiten und sind die Basis für eine Rückführbarkeit der Sensoren bzw. Analysengeräte.
The particle size distribution is considered the most relevant information for nanoscale property identification and material characterization. The current OECD test guideline on particle size and size distribution (TG 110) is not applicable to ‘nano-sized’ objects. In this project we thus develop a new OECD test guideline for the measurement of the size and size distribution of particles and fibers with at least one dimension in the range of 1 - 1000 nm. A fiber is defined as an object having an aspect ratio of length/diameter l/d >3. The width and length of each fiber should be measured concurrently.
In order to measure the particle size distributions, many techniques are available. 9 methods for particles and 2 methods for fibres have been tested in a prevalidation study and appropriate methods will be compared in an interlaboratory round robin test starting in February 2019.
UBA und BAM schlagen die Durchführung der Prüfkammermessungen bei 23 °C und 50% relativer Luftfeuchte, einer Beladung von 1,8 m²/m³ und einem Luftwechsel von 0,5 pro Stunde vor. Diese Parameter orientieren sich an der EN 16516, die als zukünftige „Referenznorm“ zu betrachten ist. Die Schmalflächenversiegelung ist auch zukünftig wie in der EN 717-1 beschrieben vorzunehmen. Nach 28 Tagen wird der Mittelwert einer Doppelbestimmung als Endkonzentration („entsprechend der Ausgleichskonzentration“) berechnet. Alternativ dazu kann die Prüfung vorzeitig abgebrochen werden, wenn an 5 Messtagen der Prüfung eine Formaldehydkonzentration von 0,1 ppm nicht überschritten wird.
Prüfungen nach der EN 717-1 sollen weiterhin gleichberechtigt möglich sein. Ergebnisse von Messungen, die nach der EN 717-1 ermittelt wurden, sind mit dem Faktor 2,0 zu multiplizieren.
Abgeleitete Verfahren wie z.B. das Gasanalyseverfahren sollen weiterhin möglich sein. Das Perforatorverfahren entfällt hier, da eine allgemeine für alle Holzwerkstoffe gültige Korrelationen nicht existiert.
Die entsprechenden Änderungen sind in der vom BMUB veröffentlichten „Bekanntmachung analytischer Verfahren für Probenahmen und Untersuchungen für die im Anhang der Chemikalien-Verbotsverordnung genannten Stoffe und Stoffgruppen“ entsprechend zu ändern.