4 Material und Umwelt
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The first manuscripts from the Qumran caves were found in 1947. Within the following 10 years, clandestine and legal excavations revealed some 900 highly fragmented manuscripts from the late Second Temple period. This collection is generally known as Scrolls of the Judea Desert or Dead Sea Scrolls (DSS). For many years after their discovery, text analysis and fragmeents attribution were the main concern of the scholars dealing with the scrolls. The uncertain archaeological provenance of the larger part of the collection added an additional difficulty to the formidable task of sorting some 19000 fragments. After 60 years of scholar research the question of origin, archaeological provenance and correct attribution of the fragmenst are still hotly debated. To dtermine a possible contribution to the debate from the point of view of writing materials, we used otpical and electron microscopy, various X-ray based techniques as well as vibratiional sprectroscopy. We validated our approach with SY - based studies using the advantages of the synchroton radiation source with respect to the benchtop devices. Our laboratory studies showed that often production and storage locality could be distinguished thenks to the specific residues ("fingerprint") they left on the material. Moreover, we have diescovered that diferrent parchment production processses coexisted in the antiquity, and the resulting writing materials can readily be distinguished.
Scientific material analysis of the elemental composition of inks from different strata of a manuscript has the potential to complement scholarly observations using palaeography and philology in reconstructing the history of the manuscript’s production, correction and repair.
There are three typologically different classes of black writing inks: soot inks consist of carbon particles.
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.
In Europe, nearly 19 Mt/y of bottom ash (BA) are produced. Of this quota, only 46 %wt. was treated, often in poorly performing plants, leaving behind 10 Mt of untreated and unrecovered BA, destined to landfill. The resulting 2.14 Mt loss of valuable materials included 1 Mt mineral fraction and 0.97 Mt ferrous metals, mostly from untreated BA, and 0.18 Mt non-ferrous metals, mostly from unrecovered BA. For the coarser fractions, the main obstacle to BA being used as recycling aggregate is the content of salts and potential toxic elements (PTEs), concentrated in a layer that coats BA particles. For the fine BA fractions, usually underexploited and landfilled, it is estimated that up to 0.95 Mt/y of ferrous and non-ferrous metals are not recovered in Europe.
During the workshop, the key results of BASH Treat project will be presented: the results of 2 industrial tests performed in BA treatment plants in Germany and Sweden; a novel dry treatment for the removal of salts and PTEs from BA coarse particles; a wet process for the recovery of heavy metal compounds from the fine fraction; a technical-economic assessment of the EU potential for the optimization of BA management.
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 %.
In recent years, the fabrication of laser-generated surface structures on metals such as titanium surfaces have gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces.
The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, laser light polarization type and direction, angle of incidence, and the effective number of laser pulses per beam spot area.
However, the characterization of the different surface structures can be difficult because of constraints regarding the analytical information from both depth and the topographic artifacts which may limit the lateral and depth resolution of elemental distributions as well as their proper quantification. A promising technique to investigate these structures even at the nano-scale is Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), a very surface sensitive technique that at the same time allows to perform depth-profiling, imaging and 3D-reconstruction of selected ion-sputter fragment distributions on the surface.
In this study we combine chemical analyses such as Energy Dispersive X-ray spectroscopy (EDX) and high-resolution scanning electron microscopy (SEM) analyses with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti and Ti alloys at different laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz), following irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment or under argon gas flow.
We show how this combined surface analytical approach allows to evaluate alteration in the surface chemistry of the laser-generated surface structures depending on the laser processing parameters and the ambient environment.
Phosphorus (P) resource availability and quality is declining and recycling P-fertilizers from waste materials are becoming increasingly important. One important secondary P resource is sewage sludge (SSL) where P is often bound as aluminum phosphate (Al-P), iron phosphate (Fe-P) and polyphosphate (poly-P), respectively. Thermal treatment in different ways is a promising way in P recycling to produce highly plant-available P-fertilizers. To investigate mechanisms behind transformation of hardly available P-species toward plant-available P forms we treated a model SSL containing different kinds of defined P sources by low-temperature conversion (LTC) at 500 °C and subsequent thermochemical treatment of the LTC product with Na additives (TCT) at 950 °C, respectively. Pot experiments with ryegrass were carried out to determine the plant availability of P of the different treatments. The poly-P (here pyrophosphates) based fertilizers had a very high plant availability after both thermal treatments. During LTC treatment the plant availability of the Fe-P and Al-P variants increased because of the Formation of Fe(II) phosphates and/or pyro-/polyphosphates. Especially the formation of Al-polyphosphate shows a high plant availability. The subsequent TCT further increased strongly the plant availability of the Fe-P variants because of the formation of highly plant-available CaNaPO4. Thus, a direct TCT without prior LTC probably also produce CaNaPO4 and is recommended for Fe-P based SSL. However, a molar Ca/P ratio of 1 in the fertilizer is favorable for CaNaPO4 formation. Thus, the knowledge on the source of primary P in SSL is essential for choosing the accurate thermal treatment method to produce highly plant-available P-fertilizers from SSL.
Over the last few years, the Federal Institute for material research (BAM, Berlin) together with the Centre for the Study of Manuscript Cultures (CSMC, University of Hamburg) have initiated a systematic material investigation of black inks produced from Late Antiquity to the Middle Ages (ca. fourth century CE–fourteenth/fifteenth centuries CE), aimed primarily at extending and complementing findings from previous sporadic studies. Part of this systematic investigation has focused on Egyptian Coptic manuscripts, and the present preliminary study is one of its outputs. It centres on a corpus of 45 Coptic manuscripts—43 papyri and 2 ostraca—preserved at the Palau-Ribes and Roca-Puig collections in Barcelona. The manuscripts come from the Monastery of Apa Apollo at Bawit, one of the largest monastic settlements in Egypt between the Late Antiquity and the Early Islamic Period (sixth–eighth centuries CE). The composition of their black inks was investigated in situ using near-infrared reflectography (NIRR) and X-ray fluorescence (XRF). The analyses determined that the manuscripts were written using different types of ink: pure carbon ink; carbon ink containing iron; mixed inks containing carbon, polyphenols and metallic elements; and iron-gall ink. The variety of inks used for the documentary texts seems to reflect the articulate administrative system of the monastery of Bawit. This study reveals that, in contrast to the documents, written mostly with carbon-based inks, literary biblical texts were written with iron-gall ink. The frequent reuse of papyrus paper for certain categories of documents may suggest that carbon-based inks were used for ephemeral manuscripts, since they were easy to erase by abrasion.
As more industrial interests focusing on using salt caverns and repurposed gas or petroleum reservoirs for alternative fuel storage, i.e. CO2/H2, the question raises whether microorganisms may impact the infrastructure, gas purity and storage condition over time.
Environments with high salinity (> 1.5 Meq of NaCl) are resided by halophiles (salt-loving microorganisms). To compensate for the intensive osmotic stress, they have resorted to two main adaptation strategies: 1) production of compatible solutes and 2) accumulation of intracellular KCl. Microbial community analysis of several high salinity environments revealed a number of recurring genera, including Halomonas and Halanaerobium. However, the impact of halophiles on the overall integrity and stability of the storage facilities remain largely unknown.
To evaluate the suitability and stability of saline storage facilities, several model halophilic microorganisms, such as members of Halomonas, will be selected as testing subjects. First, the impact of halophiles on the infrastructure will be determined using an integrative approach by combining a number of techniques, including electrochemistry, TOF-SIMS, SEM/FIB/EDS and FIB-TEM. Second, the abilities of halophiles to alter the fuel composition (i.e. increase/decrease the fractions of H2) will be monitored using gas chromatography by growing them under high pressure.
As a result of climate change and the accompanying mandatory shift to renewable energy resources, microorganisms will continue to play an important role in the energy sector, both to their benefit and detriment. Thus, it is important to achieve a certain level of understanding regarding the activities and mechanisms of halophiles prior to large-scaled excursions.
Basic oxygen furnace slags (BOFS) are by-products of the steelmaking process. Several researchers have studied the production of Portland cement clinker and metallic iron from BOFS via a reductive treatment.
In this study, we applied a carbothermal reduction of BOFS in a technical-scale electric arc furnace and characterised the clinker-like products. Those clinker-like non-metallic products (NMPs) had a chemical and mineralogical composition comparable to clinker for ordinary Portland cement (OPC) and contained large elongated alite crystals as major component. The pure NMPs reacted more slowly and achieved a lower degree of hydration compared with commercial OPC.
If the reactivity of the products can be further increased by employing specific adaptations, it can be used as a full clinker substitute for OPC. Nevertheless, it is also an option to use the material without further modifications as a cement component or concrete addition, which contributes to the strength development in both cases.
Chemical modification of wood applying benzotriazolyl-activated carboxylic acids has proven to be a versatile method for the durable functionalization of its lignocellulosic biopolymers. Through this process, the material properties of Wood can be influenced and specifically optimized. To check the scope and limitations of this modification method, various benzamide derivatives with electron-withdrawing (EWG) or electron-donating (EDG) functional groups in different positions of the aromatic ring were synthesized and applied for covalent modification of Scots pine (Pinus sylvestris L.) sapwood in this study. The bonded amounts of substances (up to 2.20 mmol) were compared with the reactivity constants of the Hammett equation, revealing a significant correlation between the modification efficiency and the theoretical reactivity constants of the corresponding aromatic substitution pattern. The successful covalent attachment of the respective substituted benzamides was proven by attenuated total reflection infrared (ATR-IR) spectroscopy, while the stability of the newly formed ester bond was proven in a standardized leaching test.
Throughout their life cycle—from production, via usage, through to disposal—materials and products interact with the environment (water, soil, air). At the same time, they are exposed to environmental influences and, through their emissions, have an impact on the environment, people, and health. Accelerated experimental testing processes can be used to predict the long-term environmental consequences of innovative products before these actually enter the environment.
The aim of this Special Issue of the journal Materials is to publish original research and review articles as well as short communications tackling the problem of reliable environmental measurement methods and reporting exemplary case studies.
Spatial Period of Laser-Induced Surface Nanoripples on PET Determines Escherichia coli Repellence
(2021)
Bacterial adhesion and biofilm formation on surfaces are associated with persistent microbial contamination, biofouling, and the emergence of resistance, thus, calling for new strategies to impede bacterial surface colonization. Using ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns), laser-induced periodic surface structures (LIPSS) featuring different submicrometric periods ranging from ~210 to ~610 nm were processed on commercial poly(ethylene terephthalate) (PET) foils. Bacterial adhesion tests revealed that these nanorippled surfaces exhibit a repellence for E. coli that decisively depends on the spatial periods of the LIPSS with the strongest reduction (~91%) in cell adhesion observed for LIPSS periods of 214 nm. Although chemical and structural analyses indicated a moderate laser-induced surface oxidation, a significant influence on the bacterial adhesion was ruled out. Scanning electron microscopy and additional biofilm studies
using a pili-deficient E. coli TG1 strain revealed the role of extracellular appendages in the bacterial repellence observed here.
In many late-breaking research fields as in photovoltaics, microelectronics, nuclear waste glasses or at least mirror glasses silver diffusion in glasses is relevant to the issues of high-level functionality and recycling. The present study is focused on silver diffusion in innovative, low-melting alkali zinc borate glasses (X2O-ZnO-B2O3, X = Li, Na, K, Rb) potentially usable for silver metallization-pastes in solar cells. The glasses were coated with a thin metallic silver layer and heat treatments in air and nitrogen close to Tg at 470 °C for 2 h were performed. After heat treatment under air and nitrogen atmospheres the coating thickness, measured by a white light interferometer, was about 1.8 µm thick. Silver depth profiles determined by means of secondary neutral mass spectrometry (SNMS) indicate the fastest silver diffusion to a depth of 3.5 µm for Li2O-ZnO-B2O3 (LZB) glass. Nevertheless, the influence of the different alkali ions on the silver diffusion is small. The oxygen availability determines the silver diffusion into the glasses. The oxygen promotes the oxidation of the silver layer enabling Ag+ to diffuse into the glass and to precipitate as Ag0. Both species were detected by x-ray absorption spectroscopy (XAS). The precipitated metallic silver particles in Na2O-ZnO-B2O3 (NZB) glass have a mean size of 5.9 nm ± 1.2 nm diameter, which was determined using transmission electron microscopy (TEM). Phase separation in zinc-rich and zinc-poor phases with a mean diameter of 75 nm ± 20 nm occurred in NZB glass after heat treatment. Ion diffusion of the glasses into the silver layer was suggested by EDX-line scans.
Antimicrobial surfaces have broad use in multiple settings including touch surfaces in hospitals, implanted devices, or consumer products. Their aim is to support existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which might drive the evolution and spread of antimicrobial resistance. In my presentation, I will highlight the risks and knowledge gaps associated with resistance on antimicrobial surfaces by different processes including evolution by de novo mutations and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed onto antimicrobial surfaces. The latter process has the potential to select for antibiotic resistance via cross-resistance between traits that confer resistance to both the antimicrobial surface coating and antibiotics. Conditions in which antibiotics and antimicrobial coatings are present simultaneously (e.g. implants) will lead to more complex interactions that can either result in the selection for or against antibiotic resistance. We mapped these interactions between several antimicrobials and antibiotics on growth and selection of Pseudomonas aeruginosa. We find prevalent physiological (i.e. synergy and antagonism) and evolutionary (i.e. cross-resistance and collateral sensitivity) combination effects. Understanding these interactions opens the door to tailor therapeutic interventions to select against resistance. In additions, we need new methods and translational studies that investigate resistance development to antimicrobial surfaces under realistic conditions. Therefore, I will present recent developments in our lab on the development of such a method based on existing efficacy standards.
Frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects) of larvae of the European house borer (EHB) and of drywood termites was tested as a natural and novel feedstock for 3D-printing of wood-based materials. Small particles produced by the drywood termite Incisitermes marginipennis and the EHB Hylotrupes bajulus during feeding in construction timber, were used. Frass is a powdery material of particularly consistent quality that is essentially biologically processed wood mixed with debris of wood and faeces. The filigree-like particles flow easily permitting the build-up of woodbased structures in a layer wise fashion using the Binder Jetting printing process. The Quality of powders produced by different insect species was compared along with the processing steps and properties of the printed parts. Drywood termite frass with a Hausner Ratio HR = 1.1 with ρBulk = 0.67 g/cm3 and ρTap = 0.74 g/cm3 was perfectly suited to deposition of uniformly packed layers in 3D printing. We suggest that a variety of naturally available feedstocks could be used in environmentally responsible approaches to scientific material sciences/additive manufacturing.
In this paper, we discuss the importance of scientifically investigating cultural artefacts in a non-invasive way. Taking as test case Leonardo da Vinci’s Manuscript with anatomic drawings and notes, which is stored in Weimar, we clarify fundamental steps in the chronology of this folio. By means of microscopy, infrared reflectography, UV photography, and X-ray fluorescence analysis, we were able to identify various types of sketching material and several varieties of iron gall ink. For his sketches, Leonardo used two different sketching tools, a lead pencil and a graphite pencil, as well as several types of ink for developing these sketches into drawings. With regard to ink, it is important to observe that there is no difference between the ink Leonardo used for drawing and the ink he used for writing text. Based on the materials analysed, we suggest a chronology for the creation of this unique folio.
Pseudomonas aeruginosa biofilms exhibit an intrinsic resistance to antibiotics and constitute a considerable clinical threat. In cystic fibrosis, a common feature of biofilms formed by P. aeruginosa in the airway is the occurrence of mutants deficient in flagellar motility. This study investigates the impact of flagellum deletion on the structure and antibiotic tolerance of P. aeruginosa biofilms, and highlights a role for the flagellum in adaptation and cell survival during biofilm development. Mutations in the flagellar hook protein FlgE influence greatly P. aeruginosa biofilm structuring and antibiotic tolerance. Phenotypic analysis of the flgE knockout mutant compared to the wild type (WT) reveal increased fitness under planktonic conditions, reduced initial adhesion but enhanced formation of microcolony aggregates in a microfluidic environment, and decreased expression of genes involved in exopolysaccharide formation. Biofilm cells of the flgE knock-out mutant display enhanced tolerance towards multiple antibiotics, whereas its planktonic cells show similar resistance to the WT. Confocal microscopy of biofilms demonstrates that gentamicin does not affect the viability of cells located in the inner part of the flgE knock-out mutant biofilms due to reduced penetration. These findings suggest that deficiency in flagellar proteins like FlgE in biofilms and in cystic fibrosis infections represent phenotypic and evolutionary adaptations that alter the structure of P. aeruginosa biofilms conferring increased antibiotic tolerance.
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.
The steel industry is an important engine for sustainable growth, added value, and high-quality employment within the European Union. It is committed to reducing its CO2 emissions due to production by up to 50% by 2030 compared to 1990′s level by developing and upscaling the technologies required to contribute to European initiatives, such as the Circular Economy Action Plan (CEAP) and the European Green Deal (EGD). The Clean Steel Partnership (CSP, a public–private partnership), which is led by the European Steel Association (EUROFER) and the European Steel Technology Platform (ESTEP), defined technological CO2 mitigation pathways comprising carbon direct avoidance (CDA), smart carbon usage SCU), and a circular economy (CE). CE ap-proaches ensure competitiveness through increased resource efficiency and sustainability and consist of different issues, such as the valorization of steelmaking residues (dusts, slags, sludge) for internal recycling in the steelmaking process, enhanced steel recycling (scrap use), the use of secondary carbon carriers from non-steel sectors as a reducing agent and energy source in the steelmaking process chain, and CE business models (supply chain analyses). The current paper gives an overview of different technological CE approaches as obtained in a dedicated workshop called “Resi4Future—Residue valorization in iron and steel industry: sustainable solutions for a cleaner and more competitive future Europe” that was organized by ESTEP to focus on future challenges toward the final goal of industrial deployment.