4 Material und Umwelt
Filtern
Dokumenttyp
- Zeitschriftenartikel (299)
- Vortrag (280)
- Posterpräsentation (138)
- Beitrag zu einem Tagungsband (43)
- Buchkapitel (23)
- Dissertation (6)
- Sonstiges (6)
- Beitrag zu einem Sammelband (5)
- Forschungsbericht (4)
- Forschungsdatensatz (3)
Sprache
- Englisch (813) (entfernen)
Schlagworte
- Biocides (50)
- Antimicrobial resistance (34)
- Corrosion (25)
- Bacteria (24)
- Biofilms (24)
- Ink (24)
- Leaching (23)
- Biofilm (19)
- MIC (19)
- Archaeometry (17)
Organisationseinheit der BAM
- 4 Material und Umwelt (813) (entfernen)
Paper des Monats
- ja (19)
This study details a theoretical analysis of leaky and waveguide modes in biperiodic all-dielectric holograms. By tuning diffraction orders and subsequently confining local density of optical states at two distinct resonance wavelengths, we present a new class of highly sensitive refractive index biosensing platforms that are capable of resolving 35.5 to 41.3 nm/RIU of spectral shift for two separate biological analytes.
Phase formation and evolution was investigated in the CaO–SiO2 system in the range of 70–80 mol% CaO. The samples were container-less processed in an aerodynamic levitation system and crystallization was followed in situ by synchrotron x-ray diffraction at the beamline P21.1 at the German electron synchrotron (DESY). Modification changes of di- and tricalcium silicate were observed and occurred at lower temperatures than under equilibrium conditions. Despite deep sample undercooling, no metastable phase formation was observed within the measurement timescale of 1 s. For the given cooling rates ranging from 300 K s−1 to about 1 K s−1, no decomposition of tricalcium silicate was observed. No differences in phase evolution were observed between reducing and oxidizing conditions imposed by the levitation gas (Ar and Ar + O2). We demonstrate that this setup has great potential to follow crystallization in refractory oxide liquids in situ. For sub-second primary phase formation faster detection and for polymorph detection adjustments in resolution have to be implemented.
For centuries, churches, secular buildings and museums have been furnished with valuable works of art. Many works of art are UV- and light-sensitive. It is well known that especially UV radiation causes damage and discoloration in paintings, textiles, plastics, wood and other materials. In particular, the wavelengths between 280 and 410 nm cause color changes, embrittlement or destruction of e.g. plastics over time. Therefore, strongly UV-absorbing glasses are advantageous for architecture and are necessary for the protection of cultural assets. As restorers in all disciplines become more and more aware, the demands placed on buildings and their furnishings in terms of climate are becoming increasingly detailed and precise. The aim in each case is to preserve the valuable artwork.
For some years now, the industry has been offering the protection of cultural objects by installing special UV-protective glasses. Currently, UV protection for church buildings is realized by laminated safety glass equipped with appropriate UV-protective plastic films. Technically, this always means a second pane of glass in front of the windows, which is installed outside the building. This creates climatic gaps that are difficult to control and deterioration due to ageing effects can be expected. At the same time, this protective glazing is not invisible and has a considerable aesthetic influence on the interior and exterior appearance of the building. Meanwhile, the preservation of historical monuments accepts such aesthetic cuts on buildings in order to protect the artwork in the interior from UV light. To this day, however, the long-term durability of UV protection provided by inserted plastic films is still controversial.
To date the only available alternative on the market is a mouth-blown UV protection glass which uses a so-called overlay to provide UV protection. This shows that UV protection can also be achieved by glasses without plastic films thus realizing an exclusive inorganic protection which normally is more stable than a polymeric one. So far there are not enough studies to prove long-term durability.
The aim of this project is to provide existing glazing or new glazing to be created with a highly transparent layer that ensures this UV-protective filter function below 400 nm. The glass coating is to be applied to the glass over a large area and fired into the surface like a classic ceramic enamel paint with the same technics. In addition, it should be long-term durable in its function. It means, that the glass has to be fused at temperatures below 630 °C during the firing process, its chemical durability has to be high, its coefficient of thermal expansion has to be as close as the one of the substrate (usually float glass) and the glass has to absorb the UV-radiation within a thin thickness (thinner as 100 µm).
In this project, the long-term durability of commercial UV-protective glasses is examined. New low melting glasses containing UV-absorbing ions are being developed. Their UV-absorption as a thin layer is analyzed as well as their chemical durability and their thermal properties.
We are grateful to BMWI for the financial support in the frame of the Central Innovation Programme for SMEs (ZIM).
Here, we describe a fast and simple extraction method for the determination of per- and polyfluorinated alkyl substances (PFASs) utilizing extractable organic fluorine (EOF) sum parameter analysis and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) in soil samples. After extraction and separation of inorganic and organic fluorinated compounds, organically bound fluorinated compounds were indirectly determined via the molecular absorption of gallium mono-fluoride at 211.248 nm. The implementation of the decisions of the “Stockholm Convention on persistent organic pollutants” as well as the “Protocol on Persistent Organic Pollutants of the Convention on Long-Range Transboundary Air Pollution” of the UNECE include the reduction respectively the elimination of PFASs in the environment. Currently, regulations aim to target single compounds (mostly C8-PFAS). But the PFAS group includes over 4700 substances, which are potentially persistent and toxic, thus target analytical approaches are not suitable for a holistic approach investigating the PFAS pollutant situation. Furthermore, forbidden PFASs are substituted by short-chain PFASs, thus the number of unknow substances is steadily increasing. For this reason, sum parameter approaches are more suitable to investigate and assess the pollution situation as well as derive exposure limits. Our developed analytical method was successfully applied to determine PFASs in soil samples from a polluted site. In view of steadily increasing numbers of PFAS substances, our method will make an important contribution in assessing the pollution situation as well as support policy makers in deriving exposure limits for PFAS in the future.
Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt für Materialforschung und -prüfung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m3. This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m3. In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28 % in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51 %.
Per- and polyfluoroalkyl substances (PFAS) have been used extensively in the past because of their inert chemical character and resistance to degradation by environmental influences. Since the beginning of their commercial use, PFAS have been widely exposed to the environment by application of PFAS in consumer products or as foaming agent in firefighting foams, thus several cases of contaminated soils sites have been reported. Since the number of known PFAS already exceeds 4700, their characterization and direct analysis is challenging given the current available techniques. Here, we introduce the novel fluorine (F) K-edge X-ray absorption near-edge structure (XANES) spectroscopy as a tool to analyze PFAS and inorganic fluorine compounds in contaminated soils and sewage sludges. While F K-edge bulk-XANES spectroscopy provide us information on the overall fluorine bonding in a sample micro X-ray fluorescence (XRF) in combination with F K-edge micro-XANES spectroscopy can also detect minor fluorine compounds and PFAS hotspots in investigated soils and sludges. Additionally, we used the combustion ion chromatography (CIC) to analyze the total amount of all PFAS as a sum parameter (extractable organic fluoride: EOF) in soils and sewage sludges. During combustion in the CIC, the PFAS in the sample get destroyed at temperatures of approx. 1000 °C and converted in inorganic fluorides that subsequently gets quantified by ion chromatography. Thus, for the first time we successfully combined F K-edge XANES spectroscopy and CIC as analytical tools to detect and quantify PFAS contaminants in soils and sewage sludges.
Bacteria generally interact with the environment via processes involving their cell-envelope. Thus, techniques that may shed light on their surface chemistry are attractive tools for providing an understanding of bacterial interactions. One of these tools is Al Kα-excited photoelectron spectroscopy (XPS) with its estimated information depth of <10 nm. XPS-analyses of bacteria have been performed for several decades on freeze-dried specimens in order to be compatible with the vacuum in the analysis chamber of the spectrometer. A limitation of these studies has been that the freeze-drying method may collapse cell structure as well as introduce surface contaminants. However, recent developments in XPS allow for analysis of biological samples at near ambient pressure (NAP-XPS) or as frozen hydrated specimens (cryo-XPS) in vacuum. In this work, we have analyzed bacterial samples from a reference strain of the Gram-negative bacterium Pseudomonas fluorescens using both techniques. We compare the results obtained and, in general, observe good agreement between the two techniques. Furthermore, we discuss advantages and disadvantages with the two analysis approaches and the output data they provide. XPS reference data from the bacterial strain are provided, and we propose that planktonic cells of this strain (DSM 50090) are used as a reference material for surface chemical analysis of bacterial systems.
In this study, nanoscopic particles of magnesium Fluoride (MgF2) and calcium fluoride (CaF2) also known as nano metal fluorides (NMFs), were evaluated for their potential to improve wood durability. Even though these fluorides are sparingly soluble, their synthesis in the form of nano-sized particles turns them into promising candidates for wood preservation. Their distinct property of low-water solubility is proposed to maintain long-lasting protection of treated wood by reducing the leaching of fluoride. Analytical methods were used to characterize the synthesized NMFs and their distribution in treated wood specimens. Transmission electron microscopy images showed that these fluoride particles are smaller than 10 nm. In nano metal fluoride (NMF) treated specimens, aggregates of these particles are uniformly distributed in the wood matrix as confirmed with scanning electron microscopy images and their corresponding energy-dispersive X-ray spectroscopy maps. The fluoride aggregates form a protective layer around the tracheid walls and block the bordered pits, thus reducing the possible flow path for water absorption into wood. This is reflected in the reduced swelling and increased hydrophobicity of wood treated with NMFs. The biocidal efficacy of NMFs was tested against brown-rot fungi (Coniophora puteanaand Rhodonia placenta), white-rot fungus (Trametes versicolor), and termites (Coptotermes formosanus). The fungal and termite tests were performed in accordance with the EN 113 (1996) and EN 117 (2012) standards, respectively. Prior to fungal tests, the NMF treated wood specimens were leached according to the EN 84 (1997)standard. Compared to untreated specimens, the NMF treated wood specimens have a higher resistance to decay caused by brown-rot fungi, white-rot fungus, and termites. Although all NMF treatments in wood reduce the mass loss caused by fungal decay, only the combined treatment of MgF2 and CaF2 has efficacy against both brown-rot fungi and white-rot fungus. Similarly, wood treated with the combined NMF formulation is the least susceptible to attack by C. formosanus.It is proposed that combining MgF2 and CaF2changes their overall solubility to promote the release of fluoride ions at the optimal concentration needed for biocidal efficacy against fungi and termites. In this thesis, it was proven that even after leaching, sufficient fluoride was present to protect NMF treated wood from fungal decay. This shows that NMFs are robust enough for above ground contact outdoor applications of wood, where permanent wetness cannot be avoided according to Use Class 3.2, as per the EN 335 (2013) standard. Also, they pose a low risk to human health and the environment because they are sparingly soluble. Since NMFs significantly reduce the decay of wood, the CO2 fixed in it will be retained for longer than in unpreserved wood. Overall, the novel results of this study show the potential of NMFs to increase the service life of building materials made from non-durable wood.
Rock-EATING FUNGI - Genetic Dive into the Biology of the Microcolonial Black Fungus Knufia petricola
(2021)
Microcolonial black fungi are a group of ascomycetes that exhibit high stress tolerance, yeast‑like growth and constitutive melanin formation. They dominate a range of hostile natural and man‑made environments, from desert rocks and salterns to dishwashers, roofs and solar panels. Due to their slow growth and a lack of genetic tools, the underlying mechanisms of black fungi’s phenotypic traits have remained largely unexplored. We chose to address this gap by genetically engineering the rock‑inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales), a species that exhibits all characteristics of black fungi. The state‑of‑the‑art genetic toolkit, together with the annotated genome sequence of strain A95, firmly established K. petricola as a model for exploring microcolonial black fungi.
MFC was used to study the corrosiveness of iron-utilizing methanogen, Methanobacterium IM1 under flow conditions. Comparing against electrical SRM, Desulfovibrio ferrophilus IS5, results showed under standard mesophilic conditions, average corrosion rates of Methanobacterium IM1 was double that of SRM. The highest corrosion rate of Methanobacterium IM1 reached up to 0.60 mm/yr under neutral conditions, and severe pitting was observed on the iron surface. Furthermore, the corrosion products of Methanobacterium IM1 were characterized with TOF-SIM, FIB-SEM and EDX, and preliminary results revealed FeCO3 is not the only corrosion product of Mi-MIC, as previously reported. Under low pH conditions, the maximum corrosion rate of Methanobacterium IM1 reached 1.57 mm/yr, which resulted in severed deformity of the iron specimen. Additional comparisons using different types of incubation material were conducted to standardize MFC MIC testing.
The survey of Canadian shale sites showed a dominance of halophilic microorganisms, including Halomonas (HA). Nitrate-amended incubations of the field samples under high salinity (14.6% NaCl), revealed a dominance of HA (>72%) and an accumulation of nitrite. Nitrite accumulation directly inhibited the growth of SRB, thereby decreasing their souring and corrosion risks. However, accumulated nitrite may also contribute to iron corrosion, which will be tested by using different concentrations of nitrate as an electron acceptor to HA. Different salinities are further tested on HA strains supplemented with iron coupons to determine their effects on iron corrosion rates. HA incubated with separate cultures of corrosive methanogen and SRB were tested to determine whether a positive or adverse effect will occur between them. Lastly, analyses of iron coupons will be conducted using TOF-SIMS, FIB-SEM and EDS for corrosion product characterization
Abstract: Since it is unknown for many applications, which PFASs are used and how they enter the environment, target analysis-based methods reach their limits. The two most frequently used sum parameters are the adsorbable organically bound fluorine (AOF) and the extractable organically bound fluorine (EOF). Both can be quantified using either combustion ion chromatography (CIC) or high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS). Here we provide an insight on the advantageous and disadvantageous of both sum parameters and both detection methods. Our study is based on the analysis of surface water samples. Next to total fluorine (TF) analysis, AOF and EOF were determined as well as CIC and HR-CS-GFMAS are compared and results are comparatively discussed. Fluorine mass balancing revealed that, the AOF/TF proportion was higher than the EOF/TF proportion. The AOF made up 0.14–0.81% of TF and the EOF 0.04–0.28% of TF. Although, organically bound fluorine represents only a small portion of TF, PFASs are of worldwide concern, because of their extreme persistence and their bioaccumulation potential. The EOF-HR-CS-GFMAS method turned out to be more precise and sensitive than the AOF-CIC method and is a promising tool for future monitoring studies/routine analysis of PFASs in the environment.
Up to now, different analytical methods for single cell analysis exist focusing on key features such as size, shape, morphology and elemental composition. The combination of the latest ICP-MS techniques - ICP-ToF-MS - together with the latest developments in the field of sample delivery - micro droplet generator (MDG) – will allow a Deep insight into the composition and size of cells.
Microbiologically influenced corrosion (MIC) is an oxidation of metals affected by the presence or activity (or both) of microorganisms e.g. Shewanella Putrefaciens in biofilms on the surface of the corroding material. As this can happen for example in the soil on iron pipes of water pipes, in oil tanks or on steel sheet piling, there is great interest in MIC research, not only from various industrial sectors, but also from the environmental aspect.
A brief perspective of BAM on nanocarriers is presented including examples with special emphasis on the characterization of such materials and underlying challenges. In this respect, also ongoing activities at BAM on different types of core/shell nanomaterials and related systems are briefly summarized.
There is an ongoing debate on European scale concerning the criticality of phosphorus. In Switzerland and Germany, phosphorus recovery from phosphorus-rich waste streams will become obligatory. Sewage sludge ash is rich in phosphorus and may become an important secondary feedstock. Thermochemical treatment of sewage sludge ash with sodium sulphate under reducing conditions was shown to remove heavy metals from the solid product and produce the fully plant available crystalline phase CaNaPO4. Pilot-scale experiments in a rotary kiln were carried out at temperatures between 750 and 1000 °C and were compared to laboratory-scale experiments with crucibles. Process upscaling was successfully demonstrated but a series of differences were noticed: In comparison to laboratory-scale, solubility of phosphorus in samples from pilot-scale experiments was lower at all chosen treatment temperatures because of shorter retention time and incomplete decomposition of sodium sulphate. X-ray diffraction analysis revealed remaining phase fractions of whitlockite (Ca3-x(Mg,Fe)x(PO4)2) and sodium sulphate from the starting materials in products and thus indicated incomplete reaction. In contrast to the results of laboratory-scale experiments, the crystalline phase CaNaPO4 was clearly absent in the products from the rotary kiln but instead a Mg-bearing phase (Ca,Mg)NaPO4 was formed. Laboratory-scale experiments confirmed (Ca,Mg)NaPO4 is an intermediate phase between whitlockite and CaNaPO4. However, both crystalline phases are characterized by high plant availability. It was shown that heavy metal removal increased at higher temperatures whereas solubility and thus plant availability of phosphorus already reached its maxima at temperatures of 950 °C in pilot-scale and 875 °C in laboratory-scale experiments.
The ISO 16000-6 standard describes a method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air by sorbent-based active sampling, thermal desorption and gas chromatography coupled with mass spectrometry (GC/MS). It also gives directions to adapt this methodology to very volatile organic compounds (VVOCs). Indeed, toxicologically based guideline values are being implemented for these compounds and it becomes necessary to measure them. But a comprehensive and robust measurement method is lacking. This work highlights the points that still need to be explored towards the standardisation of a suitable procedure: investigations on sorbent combinations, the suitability of chromatography columns and the use of gaseous standards are required. The biggest challenge remains in the fact that strong sorbents adsorb water together with VVOCs. Water may impair the analysis and the optimal approach to eliminate it is still to be found and integrated into the sampling strategy.
In the transition from carbon to iron-gall inks, the two documents from the Egyptian Museum and Papyrus Collection in Berlin with shelfmarks P 13500 and P 13501 discussed in this work present an important case. Their inks appear brownish, although they date back to the fourth and third century BCE, when carbon inks are believed to have been commonly if not exclusively used. Using imaging micro-X-ray fluorescence and infrared reflectography, we discovered that the inks in both documents contain a significant amount of copper in addition to carbon. Comparing the extant recipes for black writing inks and the experimental evidence, we suggest that these inks are a transition between the pure carbon and the iron-gall inks. Such inks may have been quite common before the production of iron-gall ink was clearly understood and established.
Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m3 emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r2 of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r2: 0.145), thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 μg/m3), especially when more conservative exposure scenarios were considered.
Test chamber measurements are an important tool to improve indoor air quality and occupational safety. Test chamber measurements are possible for a wide range of materials, products and technologies. Determination of concerning contaminants is important to ensure good indoor air quality. The detection of concerning contaminants depends on the approriate sampling and analysis.
Recycled fertilizers produced using processes for the recovery of phosphate from residual materials such as wastewater, sewage sludge and sewage sludge ashes show very good bioavailability, but it is still a product largely unknown to the market. The aim of CLOOP is therefore to document the properties and effects of such fertilizers through chemical, mineralogical and ecological analyses as well as analytical method development and pot and field plant growth trials.
Outotec focused on 3 points in CLOOP: Experimental campaigns, process simulations as well as economic analyses with focus on the AshDec process, respectively the design of a large-scale AshDec plant for phosphorus recovery. The laboratory scale trials as well as the semi-industrial scale campaign provided valuable insights into the operating parameters of the process and the plant. As a result, for example, the temperature range could be significantly lowered, and the additive addition reduced by approx. 20 %. They have further shown that the AshDec process is not susceptible to operating fluctuations and that the product can be consistently produced at high quality. With the selection of suitable operating parameters, heavy metals (As, Pb, Cd, (Zn)) can be removed. Within the campaign, about 1.5 t of fertilizer for the plant trials in CLOOP could be produced. An AshDec plant process was digitally created in simulation software, allowing valuable process parameters to be simulated at various operating parameters. On this basis, a full-scale plant was designed. The data obtained in the project were used for a detailed economic analysis including a sensitivity analysis. It was possible to show under which conditions this plant can be operated economically.
At BAM, the AshDec fertilizer was synthesized with different additives and then applied to plant experiments at Uni Bonn. The goal hereby was to check differences in plant uptake. Because of the promising results of AshDec synthesized with sodium-carbonate and because this AshDec version does not require special off gas treatment for sulfur recovery (compared to AshDec synthesized with sodium-sulfate), all project partners agreed on continuing working with this AshDec variation. It was then used as a raw P-source for formulating it into NPK-fertilizers, by granulation with ammonium-sulfate and straw ash as potassium source. These recycling fertilizers were applied to plant- and field experiments by project partners in Brazil (University of Sao Paulo) and Australia (University of Queensland). Furthermore, in leaching experiments, the solubility of phosphorus in AshDec was compared to triple super phosphate. The experiments were carried out on soils with a varying phosphorus buffering index. Results show, that the phosphorus form in AshDec is way less soluble in water. This indicates that AshDec has the potential for a so-called next generation fertilizer – a fertilizer which’s nutrients remain in the soil and supply the plant according to its needs. At the moment, this behavior gets examined more in depth in lysimeter experiments in cooperation with University of Technology Berlin.
The focus of KWB is the Life Cycle Assessment (LCA) of different NextGen fertilizers to evaluate the entire process chain from recovery to fertilizer application. The NextGen fertilizer is credited by the amount of plant available nutrients in the product, which replace nutrients from conventional fertilizer. The LCA covers N-struvite precipitation from municipal wastewater, K-struvite precipitation from industrial wastewater and the AshDec-product from sewage sludge. The LCA task is almost complete. It could be shown that struvite precipitation has comprehensive environmental benefits, mainly since positive side effects occur in sewage sludge treatment (e.g. reduced sludge volume). In principle, the energetic and ecological profile of the AshDec process compared to direct use of sewage sludge ash cannot be assessed as being generally beneficial or negative. Regarding the global warming potential, the Ashdec process shows that the expenses (e.g. energy, chemicals) cannot be covered by the P fertilizer credit. In contrast, the impact categories “terrestrial acidification potential”, and “freshwater eutrophication potential” show positive results as the credits for conventional fertilizer are higher than the burdens for the process.
At University Bonn, the standardized pot experiments were conducted with several AshDec variations, using ryegrass, soybean, and spinach on a slightly acidic sandy soil and an organic-free standard substrate. P-uptake and biomass production of different AshDec variations were generally like those of triple super phosphate and struvite, and clearly outperformed untreated sewage sludge ash and rock phosphate. Field trials in Australia and Brazil with sugarcane on acidic soils are still ongoing and results are expected by the end of 2021.