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Knufia petricola is a black fungus that colonizes sun-exposed surfaces as extreme and oligotrophic environments. As ecologically important heterotrophs and biofilm-formers on human-made surfaces, black fungi form one of the most resistant groups of biodeteriorating organisms. Due to its moderate growth rate in axenic culture and available protocols for its transformation and CRISPR/Cas9-mediated genome editing, K. petricola is used for studying the morpho-physiological adaptations shared by extremophilic and extremotolerant black fungi. In this study, the bacteria-derived tetracycline (TET)-dependent promoter (Tet-on) system was implemented to enable controllable gene expression in K. petricola. The functionality i.e., the dose-dependent inducibility of TET-regulated constructs was investigated by using GFP fluorescence, pigment synthesis(melanin and carotenoids) and restored uracil prototrophy as reporters. The newly generated cloning vectors containing the Tet-on construct, and the validated sites in the K. petricola genome for color-selectable or neutral insertion of expression constructs complete the reverse genetics toolbox. One or multiple genes can be expressed on demand from different genomic loci or from a single construct by using 2A self-cleaving peptides, e.g., for localizing proteins and protein complexes in the K. petricola cell or for using K. petricola as host for the expression of heterologous genes.
Der Band 5 der N.i.Ke.-Schriftenreihe präsentiert den aktuellen Stand materialwissenschaftlicher und bildgebender Verfahren, die bei der Untersuchung von Zeichnungen Anwendung finden. Im ersten Teil der Publikation werden die klassischen Zeichnungsträger und Zeichnungsmaterialien vorgestellt. Der mittlere Teil der Publikation beschreibt die relevanten materialwissenschaftlichen und bildgebenden Verfahren. Der letzte Teil diskutiert anhand einiger Fallbeispiele die Möglichkeiten und Grenzen der Methoden.
Antimicrobial resistance (AMR) is a global health problem. It is well known that antibiotics can drive evolutionary processes that underlie antimicrobial resistance (AMR) evolution and spread in clinical and environmental settings. In contrast, less is known about the effects of antimicrobial substances that are used as biocides (i.e. disinfectants and preservatives) on AMR evolution and spread. Biocides are present in various settings, interacting with diverse microbial communities. Therefore, it is crucial to evaluate their role in the evolution and dissemination of antimicrobial resistance. Biocides occur in a wide range of concentrations in various environmental settings. By examining how the various concentrations affect selection mechanisms, we gain insights into potential developments related to antimicrobial resistance. The aim of this PhD thesis is to investigate the effects of biocides on processes underlying resistance evolution. Specifically, the work focused on key mechanisms for resistance spread, resistance evolution, and the effect of selection pressures on evolved resistance mechanisms. The thesis is structured around three major objectives: (i) to determine the effect of biocides on the evolution of resistance by affecting the rate of occurrence of de novo mutations, (ii) to determine the effect of biocides on the spread of resistance genes by modifying the rate of horizontal gene transfer (HGT) processes, and (iii) to investigate the selective drivers of the emergence of antimicrobial resistance in adaptive laboratory evolution (ALE) experiments. De-novo mutations are spontaneous mutations that occur at a certain rate in microorganisms. The effect of biocides at subinhibitory environmentally relevant concentrations on the mutation rate in Acinetobacer baylyi, Bacillus subtilis and Escherichia coli was assessed with the fluctuation assay. The results showed that biocides affected mutation rates in a species and substance dependent matter. The bisbiguanide chlorhexidine digluconate, the quaternary ammonium compound didecyldimethylammonium chloride, the metal copper, the pyrethroid-insecticide permethrin, and the azole-fungicide propiconazole increase mutation rates in E. coli, whereas no increases were identified for B. subtilis and A. baylyi. Horizontal gene transfer refers to diverse mechanisms that mediate the transfer of mobile genetic elements between microorganisms. This work focused on conjugation and transformation. Conjugation is a process whereby a conjugative plasmid is transferred from a donor cell to a recipient cell. Transformation is a process whereby exogenous donor DNA is taken up into a recipient cell and integrated into the recipient’s’ genome. The effects of subinhibitory environmentally relevant biocide concentrations on the conjugation rate of E. coli and the transformation rate of the naturally competent organisms A. baylyi in were assessed. The results showed that benzalkonium chloride (BAC), chlorhexidine and permethrin increased conjugation in E. coli, while none of the biocides increased transformation rates in A. baylyi. To further understand the molecular mechanisms underlying the effects on mutation and conjugation rates, I investigated the induction of the RpoS-mediated general stress and the RecA-linked SOS response upon biocide exposure. The results show a link between the general stress and the SOS response with increased rates of mutation and conjugation, but not for all biocides. One major approach to study the evolutionary response of bacteria to antimicrobials are ALE experiments with growth at subinhibitory concentrations linked to serial subculturing over many generations. Such experiments have been used to study resistance evolution to antibiotics and biocides. However, previous work showed that adaptation to biocide stress may be mediated by different evolutionary drivers. Here, I investigated the contributions of evolution for increased survival as opposed to improved growth in ALE experiments with E. coli exposed to subinhibitory BAC concentrations. Two distinct evolutionary treatments selecting for survival only or survival and growth led to specific evolutionary adaptations apparent in the phenotypes and genotypes of the evolved populations. Populations growing in the presence of BAC evolved increased fitness in the presence of BAC associated with higher resistance to BAC and cross-resistance to antibiotics, while this was not the case for populations evolving for increased survival only. Genotypic characterization by whole genome sequencing of the evolved populations revealed parallelism in mutated genes among replicate populations and distinct differences across treatments. Treatments selecting for survival and growth showed mutations in stress response related genes (hslO and tufA), while selection for survival led to mutations in genes for metabolic regulation (cyaA) and cellular structure (flagella fliJ). In summary, this thesis shows that biocides affect AMR evolution and emphasizes the importance of understanding of how biocides impact the molecular and evolutionary process that underlie AMR evolution.
Advanced light weight applications like aircrafts and wind turbine blades are made of fibre reinforced plastics (FRP) with continuous fibre reinforcement and must withstand a high thermo-mechanical cyclic loading. The quality of the fibre matrix interface has a high impact on the fatigue life and was continuously improved over the years since the 50th. The fatigue life of glass fibre reinforced plastics (GFRP) used in aircraft industry is 10 to 100 times higher compared to glass fibre non crimp fabrics used for wind turbine blades.
To assure a constant and reliable high quality and strength of reinforcement fibres, synthetic fibre production is state of the art (CF, GF). There is a need for recycling GFRP and CFRP waste due to the upcoming use. Pyrolysis and solvolysis are more expensive than the mechanical route however enable a more sustainable recycling. Natural fibres and recycled synthetic fibres have a high scatter in quality and strength. Hence it is a challenge to optimize the production / recycling processes to get a reliable quality for any demanding (second life) application.
Chemical routes for using renewables resources and recycling, is going to be a good approach especially for polymer-matrix systems to get 100% quality (back) compared to the state of the art.
Finally, a proper design, life-time extension and repair is preferable to recycling to keep the carbon footprint as low as possible.
Cryomyces antarcticus, a melanized cryptoendolithic fungus endemic to Antarctica, can tolerate environmental conditions as severe as those in space. Particularly, its ability to withstand ionizing radiation has been attributed to the presence of thick and highly melanized cell walls, which—according to a previous investigation—may contain both 1,8‐dihydroxynaphthalene (DHN) and L‐3,4 dihydroxyphenylalanine (L‐DOPA) melanin. The genes putatively involved in the synthesis of DHN melanin were identified in the genome of C. antarcticus. Most important is capks1 encoding a non‐reducing polyketide synthase (PKS) and being the ortholog of the functionally characterized kppks1 from the rock‐inhabiting fungus Knufia petricola. The co‐expression of CaPKS1 or KpPKS1 with a 4′‐phosphopantetheinyl transferase in Saccharomyces cerevisiae resulted in the formation of a yellowish pigment, suggesting that CaPKS1 is the enzyme providing the precursor for DHN melanin. To dissect the composition and function of the melanin layer in the outer cell wall of C. antarcticus, non‐melanized mutants were generated by CRISPR/Cas9‐mediated genome editing. Notwithstanding its slow growth (up to months), three independent non‐melanized Δcapks1 mutants were obtained. The mutants exhibited growth similar to the wild type and a light pinkish pigmentation, which is presumably due to carotenoids. Interestingly, visible light had an adverse effect on growth of both melanized wild‐type and non‐melanized Δcapks1 strains. Further evidence that light can pass the melanized cell walls derives from a mutant expressing a H2B‐GFP fusion protein, which can be detected by fluorescence microscopy. In conclusion, the study reports on the first genetic manipulation of C. antarcticus, resulting in non‐melanized mutants and demonstrating that the melanin is rather of the DHN type. These mutants will allow to elucidate the relevance of melanization for surviving extreme conditions found in the natural habitat as well as in space.
Aschen und Schlacken aus der thermischen Abfallbehandlung stellen mit rund 25% Massenanteil die größte Reststofffraktion dar. In Deutschland fallen pro Jahr rund 6 Millionen Tonnen an. Während sich die Verwertung der metallischen Anteile problemlos gestaltet, werden an die mineralische Fraktion Anforderungen bezüglich der möglichen Freisetzung von Schwermetallen sowie Chlorid und Sulfat gestellt. In der Ersatzbaustoffverordnung sind für Aschen und Schlacken aus der Abfallverbrennung zwei Materialklassen mit unterschiedlich hohen Anforderungen an die Umweltverträglichkeit definiert. Im Rahmen eines Forschungsprojekts wurde untersucht, ob mit Abtrennung der Feinfraktion von 0–2mm die höhere Materialklasse HMVA-1 erreicht werden kann. Im Ergebnis wurde eine Verbesserung des Auslaugverhaltens erzielt, doch nicht in dem Maß, dass eine Qualität nach HMVA-1 erreicht wird. Rostaschen halten aber die Anforderungen zur Deponierung auf einer DK I-Deponie sowie die Anforderungen zur Verwertung gemäß HMVA-2 sicher ein.
The Great Pacific Garbage Patch, a significant collection of plastic introduced by human activities, provides an ideal environment to study bacterial lifestyles on plastic substrates. We proposed that bacteria colonizing the floating plastic debris would develop strategies to deal with the ultravioletexposed substrate, such as the production of antioxidant pigments. We observed a variety of pigmentation in 67 strains that were directly cultivated from plastic pieces sampled from the Garbage Patch. The genomic analysis of four representative strains, each distinct in taxonomy, revealed multiple pathways for carotenoid production. These pathways include those that produce
less common carotenoids and a cluster of photosynthetic genes. This
cluster appears to originate from a potentially new species of the Rhodobacteraceae family. This represents the first report of an aerobic anoxygenic photoheterotrophic bacterium from plastic biofilms. Spectral analysis showed that the bacteria actively produce carotenoids, such as betacarotene and beta-cryptoxanthin, and bacteriochlorophyll a. Furthermore, we discovered that the genetic ability to synthesize carotenoids is more common in plastic biofilms than in the surrounding water communities. Our findings suggest that plastic biofilms could be an overlooked source of bacteria-produced carotenoids, including rare forms. It also suggests that photoreactive molecules might play a crucial role in bacterial biofilm communities in surface water.
Obwohl der Leichtbau mit carbonfaserverstärkten Kunststoffen (CFK) einen wichtigen Beitrag zum Klimaschutz und zur Ressourceneffizienz liefert, stellt der wachsende Abfallstrom von aktuell 62 kt/a eine große Herausforderung dar. Weil die Produktion von Carbonfasern (CF) überwiegend auf fossilen Rohstoffen basiert und sehr energieintensiv ist, werden nachhaltige Recyclinglösungen dringend benötigt. Hier wird ein Überblick über aktuelle Recyclingprozesse gegeben und deren Limitierungen diskutiert. Darüber hinaus wird eine Möglichkeit zur sicheren chemischen Nutzung von CF-haltigen Reststoffen aufgezeigt, die nicht zur Wiederverwertung geeignet sind. Das Projekt CF Pyro untersucht deren Einsatz als Sekundärrohstoff in der Pyrometallurgie und setzt besondere Schwerpunkte bei der Reaktivität von CF, der Prozessstabilität und der Vermeidung von Emissionen gesundheitsschädlicher WHO-Fasern. Abschließend wird eine, auf den experimentellen Ergebnissen und im Dialog mit Expertinnen und Experten aus Wirtschaft, Wissenschaft und Politik entwickelten, Technologiebewertung vorgestellt.
Obwohl der Leichtbau mit carbonfaserverstärkten Kunststoffen (CFK) einen wichtigen Beitrag zum Klimaschutz und zur Ressourceneffizienz liefert, stellt der wachsende Abfallstrom von aktuell 62 kt/a eine große Herausforderung dar. Weil die Produktion von Carbonfasern (CF) überwiegend auf fossilen Rohstoffen basiert und sehr energieintensiv ist, werden nachhaltige Recyclinglösungen dringend benötigt. Hier geben wir einen Überblick über aktuelle Recyclingprozesse und diskutieren deren Limitierungen. Darüber hinaus zeigen wir eine Möglichkeit zur sicheren chemischen Nutzung von CF-haltigen Reststoffen auf, die nicht zur Wiederverwertung geeignet sind. Das Projekt CF Pyro untersucht deren Einsatz als Sekundärrohstoff in der Pyrometallurgie und setzt besondere Schwerpunkte bei der Reaktivität von CF, der Prozessstabilität und der Vermeidung von Emissionen gesundheitsschädlicher WHO-Fasern. Nach der Präsentation der Projektergebnisse erfolgte in der Diskussion mit Expertinnen und Experten aus Wirtschaft, Wissenschaft und Politik eine Technologiebewertung für die Nutzung von CF in pyrometallurgischen Prozessen.
The classification of incineration bottom ash (IBA) as hazardous or non-hazardous according to ecotoxic hazard property HP14 is still under debate. In this context, only the compounds of Zn and Cu with the hazard statement code H410 are of relevance. With an approach based on the grouping of substances, it was shown that such substances are either readily water-soluble or slightly and sparingly soluble. The concentrations of readily soluble Cu and Zn compounds in IBA are far below the cut-off value of 0.1%. Slightly and sparingly soluble Zn and Cu compounds could be quantified in the first fraction of a four-step sequential extraction procedure. With the results from the complete sequence, the dimensionless synthesis toxicity index (STI) was calculated and was in the range of 494 to 1218 for the four investigated IBA samples. It was concluded that IBA can usually be classified as non-hazardous.
AbstractThe correlation between altered extracellular pH and various pathological conditions, including cancer, inflammation and metabolic disorders, is well known. Bulk pH measurements cannot report the extracellular pH value at the cell surface. However, there is a limited number of suitable tools for measuring the extracellular pH of cells with high spatial resolution, and none of them are commonly used in laboratories around the world. In this study, a versatile ratiometric nanosensor for the measurement of extracellular pH was developed. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with the pH-inert reference dye Nile red and is surface functionalized with a pH-responsive fluorescein dye. Equipped with a targeting moiety, the nanosensor can adhere to cell membranes, allowing direct measurement of extracellular pH at the cell surface. The nanosensor exhibits a sensitive ratiometric pH response within the range of 5.5–9.0, with a calculated pKa of 7.47. This range optimally covers the extracellular pH (pHe) of most healthy cells and cells in which the pHe is abnormal, such as cancer cells. In combination with the nanosensors ability to target cell membranes, its high robustness, reversibility and its biocompatibility, the pHe nanosensor proves to be well suited for in-situ measurement of extracellular pH, even over extended time periods. This pH nanosensor has the potential to advance biomedical research by improving our understanding of cellular microenvironments, where extracellular pH plays an important role.
Detektion, Quantifizierung und Entfernung von insbesondere ultrakurzkettigen PFAS in Grundwasser
(2024)
Da PFAS in großem Umfang in einer Vielzahl von Produkten verwendet wurde, sind sie im Grundwasser in der Nähe vieler industrieller und militärischer Anlagen weltweit zu finden. Darüber hinaus führten neue Vorschriften und Beschränkungen für die Verwendung von langkettigen PFAS zu einer vermehrten Produktion kurzkettiger Alternativen. Ultrakurzkettige PFAS (≥C3) können natürliche und anthropogene Barrieren durchdringen und schließlich in Trinkwasserquellen gelangen. Zudem entfernen die meisten gängigen Trinkwasser-aufbereitungsverfahren die ultrakurzkettigen PFAS nicht ausreichend. Im Kooperationsprojekt DEFEAT-PFAS wird daher das Ziel verfolgt, Wissenslücken über Nachweis, Quantifizierung und Entfernung von kurz- (C4-C7) und ultrakurzkettige (C1-C3) PFAS, in kontaminiertem Grundwasser zu schließen. Die israelischen und deutschen Projektpartner entwickeln dafür analytische Methoden and selektive Passivsammler, um das zeitliche Profil von PFAS-Spezies im Grundwasser zu erfassen und überwachen. Darüber hinaus ein zweistufiges Verfahren entwickelt, welches darauf ausgelegt ist, die relativ niedrigen PFAS-Konzentrationen im Grundwasser durch neuartige Membranverfahren, Umkehrosmose im Batchbetrieb mit geschlossenem Kreislauf sowie Verbund-Nanofiltrationsmembranen, zu konzentrieren. Anschließend werden die PFAS angereicherten Konzentrate mittels Koagulation behandelt und das verbleibende PFAS an kohlenstoffhaltigen Nanomaterialien adsorbiert.
The research project focuses on tackling the detection, measurement, and elimination of per- and polyfluoroalkyl substances (PFAS) from polluted groundwater, with a particular emphasis on addressing short (C4-C7) and ultrashort (C1-C3) chain PFAS. Given the widespread use of PFAS in various products, they are commonly found in groundwater near industrial and military sites in Germany and Israel. Moreover, recent regulations limiting the use of long chain PFAS have led industries to shift towards shorter chain alternatives. Hence, our efforts are geared towards refining detection, quantification, and removal methods for short and ultrashort chain PFAS. In terms of detection, ww are developing passive sampling devices capable of collecting and tracking the temporal distribution of PFAS species in groundwater. This will enable us to analyze contaminations in German and Israeli groundwater using cutting-edge analytical techniques. Additionally, contaminated groundwater will undergo a two-stage treatment process aimed at concentrating the relatively low PFAS concentrations using innovative membrane technologies such as closed-circuit reverse osmosis and mixed matrix composite nanofiltration membrane adsorbers. Subsequently, the streams containing higher PFAS concentrations will be treated through coagulation, with the remaining PFAS being adsorbed onto carbonaceous nanomaterials. The outcome of this research will include the creation of advanced tools for detecting, measuring, and eliminating PFAS from polluted groundwater, while also enhancing our understanding of the scope of these contaminations.
Ultrashort PFAS (≤ 3 carbon atoms) were overlooked for a long time in analytical monitoring. Beside through the use of these substances, they contribute to the PFAS background in the environment through (environmental/ bio-) degradation and incomplete destruction3 of PFAS with longer carbon chains or other fluorinated compounds. As part of the German-Israeli Cooperation in Water Technology Research project „Detection, quantification, and treatment of per- and polyfluoroalkyl substances in groundwater“ (DEFEAT-PFAS), we are developing an as simple as possible direct headspace (HS-)GC-MS method to detect trifluoroacetic acid (TFA) and perfluoropropanioc acid (PFPrA), as well as trifluoroethanol (TFEtOH), pentafluoropropanol(PFPrOH) and hexafluoroiospropanol (HFIP) in water samples. Here we present the results of the PFAS mentioned in spiked ultrapure water solutions.
Per- and polyfluoroalkyl substances (PFAS) have been extensively utilized in various industrial processes, resulting in elevated concentrations in landfills and drinking water reservoirs. Despite recognizing that shortchained
PFAS are harmful, they are often overlooked. Short-chain PFAS are more challenging to remove via adsorption and membrane separation processes, and their detection is complex, thus creating a critical gap in understanding their environmental impact. To improve their environmental monitoring, we aim to improve short-chain PFAS adsorption and electro-sorption on novel carbon-based adsorbers such as pristine and functionalized multi-walled carbon nanotubes (MWCNTs) and assess their adsorption mechanisms. Based on the obtained result, we aim to develop a PFAS passive sampling device.
Detection, Quantification and Treatment of Per and Polyfluoroalkyl substances (PFAS) in Groundwater
(2024)
The research project focuses on tackling the detection, measurement, and elimination of per- and polyfluoroalkyl substances (PFAS) from polluted groundwater, with a particular emphasis on addressing short (C4-C7) and ultrashort (C1-C3) chain PFAS. Given the widespread use of PFAS in various products, they are commonly found in groundwater near industrial and military sites in Germany and Israel. Moreover, recent regulations limiting the use of long chain PFAS have led industries to shift towards shorter chain alternatives. Hence, our efforts are geared towards refining detection, quantification, and removal methods for short and ultrashort chain PFAS. In terms of detection, ww are developing passive sampling devices capable of collecting and tracking the temporal distribution of PFAS species in groundwater. This will enable us to analyze contaminations in German and Israeli groundwater using cutting-edge analytical techniques. Additionally, contaminated groundwater will undergo a two-stage treatment process aimed at concentrating the relatively low PFAS concentrations using innovative membrane technologies such as closed-circuit reverse osmosis and mixed matrix composite nanofiltration membrane adsorbers. Subsequently, the streams containing higher PFAS concentrations will be treated through coagulation, with the remaining PFAS being adsorbed onto carbonaceous nanomaterials. The outcome of this research will include the creation of advanced tools for detecting, measuring, and eliminating PFAS from polluted groundwater, while also enhancing our understanding of the scope of these contaminations.
In order to protect natural gypsum deposits and to compensate for the decreasing amount of Flue Gas Desulfurization (FGD) gypsum it is necessary to develop and explore new sources of gypsum. For this purpose, the potentials of different gypsum wastes are investigated in the study “GipsRec 2.0”, funded by the Federal Ministry of Education and Research (Germany).
On the one hand, the project worked on a new processing technology for gypsum fiberboards (GFB). While the recycling of gypsum plasterboards has already been carried out on an industrial scale for several years, the recycling of gypsum fiberboards (GFB) has proven to be challenging. Gypsum fiberboards from demolition sites and offcuts from GFB production were used for these investigations. The tests were conducted on a technical scale. Furthermore, various synthetic gypsums are being investigated with regard to their suitability for gypsum production. The analyses are carried out on production residues.
In this project, a promising process for gypsum fiberboard recycling could be developed, as well as other waste gypsums are investigated and evaluated with regard to their potential as secondary raw material. In addition, selected process routes are assessed for their environmental impact using a life cycle assessment (LCA) approach.
Gips gehört zu den nachgefragtesten Baustoffen und entsprechend steigt der Gipsverbrauch weltweit schon seit Jahrzehnten an. In Deutschland wird der Gipsbedarf seit vielen Jahren zu einem guten Teil durch REA-Gips, einem Nebenprodukt aus der Abgasreinigung von Kohlekraftwerken, gedeckt. Die weitere Gipsversorgung erfolgt größtenteils durch die Nutzung natürlicher Gipsvorkommen. Ein geringer, aber steigender Anteil an RC-Gips aus dem Baustoffrecycling und die Nutzung synthetischer Gipse aus Nebenprodukten anderer Industriezweige sind ebenfalls zu verzeichnen. Aufgrund der nationalen Klimaschutzziele und der damit verbundenen Abschaltung von Kohlekraftwerken wird das REA-Gipsangebot in den nächsten Jahren jedoch weiter deutlich zurückgehen, so dass andere Gipsquellen erschlossen werden müssen.
Abhängig von der Lebensdauer der verwendeten Gipsprodukte im Bausektor ist infolge des in den vergangenen Jahren erfolgten Anstiegs des Gipsverbrauchs auch mit einer Zunahme von Gipsresten in Bau- und Abbruchabfällen zu rechnen. Im Hinblick auf eine bevorstehende Verknappung von Gips wird die Rückgewinnung dieser Gipse aus Bau- und Abbruchabfällen immer wichtiger. Das Recycling von Gipskartonplatten ist mittlerweile eine etablierte Technik und wird bereits seit einigen Jahren in industriellem Maßstab durchgeführt. Außerdem werden neue Verfahren zur Wiederverwertung weiterer Gipsprodukte aus Rück- und Umbaumaßnahmen untersucht. Von besonderem Interesse sind verschiedene Arten von Gipsplatten, da sie gut für selektiven Rückbau geeignet sind. Daher können sie vergleichsweise frei von Verunreinigungen oder Störstoffen zurückgewonnen werden, was für das Gipsrecycling besonders wichtig ist.
In dem vom Bundesministerium für Bildung und Forschung geförderten Forschungsprojekt "GipsRec 2.0" werden technische, wirtschaftliche und ökologische Aspekte des Recyclings von Gipsfaserplatten sowie von verschiedenen Synthesegipsen untersucht und bewertet. Die Aufbereitung von Gipsfaserplatten erfolgte im halbtechnischen Maßstab, an verschiedenen potentiellen Ausgangsstoffen für synthetische Gipse wurden Laborversuche durchgeführt. Erfolgversprechende Verfahrenswege werden ökobilanziell bewertet. Ziel dieser Arbeiten ist die Erschließung der Sekundärrohstoffpotenziale von weiteren Quellen für die RC-Gipsproduktion um mit einer Steigerung des Gipsrecyclings die in naher Zukunft durch die Reduktion der REA-Gips-Bereitstellung entstehende Lücke in der Rohstoffversorgung zu verringern.
In order to protect natural gypsum deposits and to compensate for the decreasing amount of Flue Gas Desulfurization (FGD) gypsum it is necessary to develop and explore new sources of gypsum. For this purpose, the potentials of different gypsum wastes are investigated in the study “GipsRec 2.0”, funded by the Federal Ministry of Education and Research (Germany).
On the one hand, the project worked on a new processing technology for gypsum fiberboards (GFB). While the recycling of gypsum plasterboards has already been carried out on an industrial scale for several years, the recycling of gypsum fiberboards (GFB) has proven to be challenging. Gypsum fiberboards from demolition sites and offcuts from GFB production were used for these investigations. The tests were conducted on a technical scale. Furthermore, various synthetic gypsums are being investigated with regard to their suitability for gypsum production. The analyses are carried out on production residues.
In this project, a promising process for gypsum fiberboard recycling could be developed, as well as other waste gypsums are investigated and evaluated with regard to their potential as secondary raw material. In addition, selected process routes are assessed for their environmental impact using a life cycle assessment (LCA) approach.
Die Einstufung von Hausmüllverbrennungsasche (IBA) als gefährlich oder nicht gefährlich nach der Gefahreneigenschaft HP14 (ökotoxisch) ist nach wie vor umstritten, da es noch keine keine allgemein anerkannten Methoden zur Bewertung gibt. Wenn die Berechnungsregeln angewendet werden sollen angewendet werden sollen, sind Kenntnisse über die chemische Zusammensetzung von IBA erforderlich. Informationen über über die chemische Zusammensetzung von IBA können mit einem Ansatz gewonnen werden, der auf der Gruppierung von Substanzen. Für IBA können vier Stoffgruppen definiert werden: 1. elementare und legierte Metalle, 2. leicht wasserlösliche Stoffe, 3. schwer lösliche Stoffe und 4. Stoffe mit starken chemischen Bindungen. Elementares und legiertes Cu und Zn sind in der IBA vorhanden und werden in der Regel als Nichteisenmetallfraktion zurückgewonnen, zumindest die größeren Partikel. Zn-Partikel, die kleiner als 1 mm sind, werden als H410 eingestuft, feine Partikel von Cu nur als H411. Die wasserlösliche Fraktion kann mit Standardauslaugungsmethoden quantifiziert werden Auslaugungsmethoden quantifiziert werden, z. B. bei einem Flüssigkeits-Feststoff-Verhältnis (L/S) von 2 oder 10 l/kg. Sowohl die Sulfate von Zn als auch von Cu gehören zu dieser Gruppe. In einer neueren Veröffentlichung wurde gezeigt, dass bei den oben genannten Metalle die ausgelaugte Menge weit unter dem Grenzwert von 1.000 mg/kg liegt, selbst wenn stöchiometrische Faktoren angewendet werden. Stoffgruppe 3 sind potenzielle H410-Stoffe. Dabei handelt es sich um Carbonate, Hydroxide und Oxide der betreffenden Elemente, die löslich sind in schwachen organischen Säuren wie Essigsäure löslich sind. Die Worst-Case-Stoffe der Gruppe 3, d. h. die Verbindungen mit den höchsten stöchiometrischen Faktoren, sind CuCO3xCu(OH)2 und ZnO. Stoffe mit starken chemischen Bindungen wie Silikate oder Sulfide sind nur löslich in starken Säuren (z.B. Königswasser) löslich und haben keinen Ökotoxizitäts-Gefahrencode. Das Mobilisierungsverhalten der relevanten Schwermetalle und damit der Gruppe der schwer schwerlöslichen Verbindungen kann mit der 4-stufigen sequentiellen Extraktion untersucht werden. Für die HP14 Einstufung könnte auch eine einstufige Extraktion ausreichend sein. Nur die Elemente Zn und Cu sind für die HP14-Einstufung der IBA von Bedeutung, da die Feststoffgehalte aller anderen Schwermetalle unterhalb des Feststoffgehalte aller anderen Schwermetalle unter der Cut-Off-Grenze von 0,1 % liegen, selbst wenn man sie in chemischen Verbindungen mit stöchiometrischen Faktoren. Im Ergebnis wurde gezeigt, dass IBA in der Regel als nicht gefährlich einzustufen ist.
Die Einstufung von Hausmüllverbrennungsasche (HMVA) als gefährlich oder nicht gefährlich nach der Gefahreneigenschaft HP14 (ökotoxisch) ist nach wie vor umstritten, da es noch keine allgemein anerkannten Methoden zur Bewertung gibt. Wenn die Berechnungsregeln angewendet werden sollen angewendet werden sollen, sind Kenntnisse über die chemische Zusammensetzung von HMVA erforderlich. Informationen über die chemische Zusammensetzung von HMVA können mit einem Ansatz gewonnen werden, der auf der Gruppierung von Substanzen. Für HMVA können vier Stoffgruppen definiert werden: 1. elementare und legierte Metalle, 2. leicht wasserlösliche Stoffe, 3. schwer lösliche Stoffe und 4. Stoffe mit starken chemischen Bindungen. Elementares und legiertes Cu und Zn sind in der HMVA vorhanden und werden in der Regel als Nichteisenmetallfraktion zurückgewonnen, zumindest die größeren Partikel. Zn-Partikel, die kleiner als 1 mm sind, werden als H410 eingestuft, feine Partikel von Cu nur als H411. Die wasserlösliche Fraktion kann mit Standardauslaugungsmethoden quantifiziert werden Auslaugungsmethoden quantifiziert werden, z. B. bei einem Flüssigkeits-Feststoff-Verhältnis (L/S) von 2 oder 10 l/kg. Sowohl die Sulfate von Zn als auch von Cu gehören zu dieser Gruppe. In einer neueren Veröffentlichung wurde gezeigt, dass bei den oben genannten Metalle die ausgelaugte Menge weit unter dem Grenzwert von 1.000 mg/kg liegt, selbst wenn stöchiometrische Faktoren angewendet werden. Stoffgruppe 3 sind potenzielle H410-Stoffe. Dabei handelt es sich um Carbonate, Hydroxide und Oxide der betreffenden Elemente, die löslich sind in schwachen organischen Säuren wie Essigsäure löslich sind. Die Worst-Case-Stoffe der Gruppe 3, d. h. die Verbindungen mit den höchsten stöchiometrischen Faktoren, sind CuCO3xCu(OH)2 und ZnO. Stoffe mit starken chemischen Bindungen wie Silikate oder Sulfide sind nur löslich in starken Säuren (z.B. Königswasser) löslich und haben keinen Ökotoxizitäts-Gefahrencode. Das Mobilisierungsverhalten der relevanten Schwermetalle und damit der Gruppe der schwer schwerlöslichen Verbindungen kann mit der 4-stufigen sequenziellen Extraktion untersucht werden. Für die HP14 Einstufung könnte auch eine einstufige Extraktion ausreichend sein. Nur die Elemente Zn und Cu sind für die HP14-Einstufung der HMVA von Bedeutung, da die Feststoffgehalte aller anderen Schwermetalle unterhalb des Feststoffgehalte aller anderen Schwermetalle unter der Cut-Off-Grenze von 0,1 % liegen, selbst wenn man sie in chemischen Verbindungen mit stöchiometrischen Faktoren. Im Ergebnis wurde gezeigt, dass HMVA in der Regel als nicht gefährlich einzustufen ist.
Introduction: Effective disinfection is crucial to maintain hygiene and to prevent the spread of infections. Phenotypic heterogeneity in disinfection survival (i.e. tolerance) may result in failure of disinfection, which in turn may foster the evolution of resistance to both disinfectants and antibiotics. However, the consequences of phenotypic heterogeneity for disinfection outcome and resistance evolution are not well understood. Goal: This study investigates the impact of phenotypic heterogeneity on the survival and evolution of Escherichia coli during disinfection with six commonly used substances. Furthermore, the consequences of evolved disinfectant tolerance for antibiotic resistance evolution are studied. Materials & Methods: The extent of population heterogeneity during disinfection is derived by determining time-kill kinetics and analysis with mathematical modelling. The link between population heterogeneity and evolvability of disinfectant tolerance was assessed by laboratory evolution experiments under periodic disinfection. The ability of disinfectant tolerant strains to evolve antibiotic resistance is assessed by serial transfer experiments with increasing concentrations of different antibiotics and by whole genome sequencing. Results: Multi-modal time-kill kinetics in three of the six disinfectants suggest the presence of disinfectant-tolerant subpopulations (i.e. persister cells). Importantly, the ability and extent to evolve population-wide tolerance under periodic disinfection is related with the presence of persister cells and the level of phenotypic heterogeneity during disinfection. Interestingly, the probability of high-level resistance evolution to certain antibiotics is attenuated in disinfectant tolerant strains as compared to the sensitive ancestor. Whole-genome sequencing reveals epistatic interactions between disinfectant tolerance and antibiotic resistance mutations, preventing access to canonical evolutionary paths to resistance. Summary: Our findings suggest that phenotypic heterogeneity can facilitate disinfection survival and the evolution of population wide tolerance, which can impact future antibiotic resistance evolution.
The biogenesis of iron–sulfur (Fe/S) proteins entails the synthesis and trafficking of Fe/S clusters, followed by their insertion into target apoproteins. In eukaryotes, the multiple steps of biogenesis are accomplished by complex protein machineries in both mitochondria and cytosol. The underlying biochemical pathways have been elucidated over the past decades, yet the mechanisms of cytosolic [2Fe-2S] protein assembly have remained ill-defined. Similarly, the precise site of glutathione (GSH) requirement in cytosolic and nuclear Fe/S protein biogenesis is unclear, as is the molecular role of the GSH-dependent cytosolic monothiol glutaredoxins (cGrxs). Here, we investigated these questions in human and yeast cells by various in vivo approaches. [2Fe-2S] cluster assembly of cytosolic target apoproteins required the mitochondrial ISC machinery, the mitochondrial transporter Atm1/ABCB7 and GSH, yet occurred independently of both the CIA system and cGrxs. This mechanism was strikingly different from the ISC-, Atm1/ABCB7-, GSH-, and CIA-dependent assembly of cytosolic–nuclear [4Fe-4S] proteins. One notable exception to this cytosolic [2Fe-2S] protein maturation pathway defined here was yeast Apd1 which used the CIA system via binding to the CIA targeting complex through its C-terminal tryptophan. cGrxs, although attributed as [2Fe-2S] cluster chaperones or trafficking proteins, were not essential in vivo for delivering [2Fe-2S] clusters to either CIA components or target apoproteins. Finally, the most critical GSH requirement was assigned to Atm1-dependent export, i.e. a step before GSH-dependent cGrxs function. Our findings extend the general model of eukaryotic Fe/S protein biogenesis by adding the molecular requirements for cytosolic [2Fe-2S] protein maturation.
Any surface in the environment acts as hotspot for microbial attachment and activity. These biofilms represent the interface between humans and the environment.
While in the past biofilms were often seen as disturbance, we now start to understand the enormous potential of beneficial biofilms. They can be used in a broad range of applications and are sources for new microorganisms and traits. After all, biofilms represent a great example for a collaborative lifestyle.
The Microplastic Microbiome
(2024)
Microplastics represent man-made and newly emerging surfaces in our ecosystems, where they interact with microorganisms. The ecosystem in focus of this presentation will be the aquatic environment. It will be portrayed, which microorganisms use microplastics as a habitat, how environmental factors shape this colonization, and why the biodegradation of plastics in the ocean is an overall unlikely process. We will also discuss whether potentially pathogenic microorganisms use microplastics as a raft. Finally, possible adaptation mechanisms of plastic-colonizing microorganisms will be presented, such as the production of photoreactive molecules. The microplastic microbiome has a large potential to harbor so far unknown species with curious traits, representing an exciting research topic for the future.
In this study, we investigated the diverse range of materials used for sizing in Iranian paper manuscripts during the Timurid (fifteenth century) to Safavid (sixteenth century) and Qajar (nineteenth century) periods. Our approach combined historical analysis with scientific examination of reconstructed sizings. We reconstructed 15 sizing materials based on identified Persian historical recipes and analysed their physical, optical, and spectral characteristics. Additionally, we assessed their behaviour against the mould fungus Aspergillus flavus. The results revealed distinctive properties for each sizing material, shedding light on their potential applications in paper preservation. Furthermore, our investigation demonstrated variations in hygroscopicity, thickness, grammage, and ash content post-sizing. The sizing materials also exhibited different effects on paper reflectance properties. Additionally, our study revealed insights into the impact of sizing on burnished papers, indicating that the mechanical process of burnishing did not significantly alter the chemical composition or spectral properties of the paper, with only minor changes in brightness observed in specific cases. All tested sizing materials supported varying levels of mould growth, indicating potential implications for paper conservation. Our findings provide valuable insights into the historical practices of Iranian paper sizing and offer practical considerations for the preservation of paper manuscripts.
Understanding Stimulation of Conjugal Gene Transfer by Nonantibiotic Compounds: How Far Are We?
(2024)
A myriad of nonantibiotic compounds is released into the environment, some of which may contribute to the dissemination of antimicrobial resistance by stimulating conjugation. Here, we analyzed a collection of studies to (i) identify patterns of transfer stimulation across groups and concentrations of chemicals, (ii) evaluate the strength of evidence for the proposed mechanisms behind conjugal stimulation, and (iii) examine the plausibility of alternative mechanisms. We show that stimulatory nonantibiotic compounds act at concentrations from 1/1000 to 1/10 of the minimal inhibitory concentration for the donor strain but that stimulation is always modest (less than 8-fold). The main proposed mechanisms for stimulation via the reactive oxygen species/SOS cascade and/or an increase in cell membrane permeability are not unequivocally supported by the literature. However, we identify the reactive oxygen species/SOS cascade as the most likely mechanism. This remains to be confirmed by firm molecular evidence. Such evidence and more standardized and high-throughput conjugation assays are needed to create technologies and solutions to limit the stimulation of conjugal gene transfer and contribute to mitigating global antibiotic resistance.
Microbially induced carbonate precipitation (MICP), a widespread phenomenon in nature, is gaining attention as a low-carbon alternative to ordinary Portland cement (OPC) in geotechnical engineering and the construction industry for sustainable development. In the Philippines, however, very few works have been conducted to isolate and identify indigenous, urease-producing (ureolytic) bacteria suitable for MICP. In this study, we isolated seven, ureolytic and potentially useful bacteria for MICP from marine sediments in Iligan City. DNA barcoding using 16s rDNA identified six of them as Pseudomonas stutzeri, Pseudomonas pseudoalcaligenes, Bacillus paralicheniformis, Bacillus altitudinis, Bacillus aryabhattai, and Stutzerimonas stutzeri but the seventh was not identified since it was a bacterial consortium. Bio-cementation assay experiments showed negligible precipitation in the control (without bacteria) at pH 7, 8, and 9. However, precipitates were formed in all seven bacterial isolates, especially between pH 7 and 8 (0.7–4 g). Among the six identified bacterial species, more extensive precipitation (2.3–4 g) and higher final pH were observed in S. stutzeri, and B. aryabhattai, which indicate better urease production and decomposition, higher CO2 generation, and more favorable CaCO3 formation. Characterization of the precipitates by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR) confirmed the formation of three carbonate minerals: calcite, aragonite, and vaterite. Based on these results, all six identified indigenous, ureolytic bacterial species from Iligan City are suitable for MICP provided that the pH is controlled between 7 and 8. To the best of our knowledge, this is the first report of the urease-producing ability and potential for MICP of P. stutzeri, P. pseudoalcaligenes, S. stutzeri, and B. aryabhattai.
Per- and polyfluoroalkyl substances (PFAS) were classified as a group of highly concerning chemicals over the last decades. Because of the high persistence of PFAS, their previous use led to contamination of the environment and human population. Due to ongoing use and incomplete remediation or destruction methods, the PFAS background in the environment is growing continuously.
The presence of ultrashort PFAS (with ≤3 carbon atoms) in the environment is often overlooked despite their contributions to PFAS levels. These compounds may directly contaminate the environment and arise from degradation of polyfluorinated compounds as well as incomplete PFAS destruction in certain industrial processes. Nonetheless, few approaches for targeted analysis of ultrashort PFASs have been developed, except for trifluoroacetic acid (TFA). Beside liquid (LC-MS/MS), supercritical fluid (SFC-MS/MS), and ion chromatography (IC-MS)-based systems, gas chromatography coupled with mass spectrometry (GC-MS) is a promising method for detection and quantification of ultrashort PFAS.
The goal of this study was to develop a simple headspace GC-MS method for the quantification of ultrashort perfluorocarboxylic acids (PFCAs) and polyfluorinated alcohols (PFOHs) in water samples. In contrast to PFOHs, functionalization of PFCAs was required for quantification. This was done by esterification with methanol at 80 °C, which can be carried out directly in the headspace GC-MS system.
Moreover, several parameters were optimized to achieve a low limit of quantification (LOQ) for the analytes used: i) The ratio of the aqueous solution, methanol, and available gas phase within the analysis vessel, ii) the concentration of additional acid in esterification mixtures of PFCAs, iii) shaking frequency and iv) shaking time before analysis. After optimizing the procedure, we were able to quantify ultrashort PFCAs and PFOHs. Thus, our developed headspace GC-MS method has the potential to be used as an alternative target analysis for ultrashort-chain PFCAs and PFOHs in various water samples (groundwater, wastewater).
Zusammenfassend wurde in dieser Arbeit gezeigt, dass die Setzmaschinentechnik eine geeignete Methode ist, um Brechsande aus gemischten Bauabfällen aufzubereiten. Die Trennung des Materials in zwei Stoffströme unterschiedlicher Dichte hat sich mit einer Absenkung um 56% besonders effizient in der Reduzierung von PAK Belastungen im Feststoff erwiesen. Auch die Sulfatlast im Produktstrom wurde durch den Prozess im Vergleich zum Aufgabegut um 29% gesenkt. Neben der Erhöhung des Median Partikeldurchmessers durch Klassierungseffekte, ist die Herabsetzung verschiedener Eluatparameter ebenfalls positiv zu bewerten. Dies bezieht sich zum einen auf die elektrische Leitfähigkeit, die nach EBV von RC-3 auf RC-1 aufgewertet wurde und zum anderen auf die Chromkonzentration, die von RC-2 auf die Stufe RC-1 angehoben wurde. Die vorliegenden Aufbereitungsergebnisse erlaubten jedoch nicht eine Gesamteinordnung des Materials als Ersatzbaustoff oberhalb der Klasse RC-3. Hierzu ist eine weitere Absenkung der Eluatwerte für Sulfat um 25% von RC-3 (1325 mg L-1) auf RC-2 (< 1000 mg L-1) und des PAK-15 Wertes um 4% von RC-3 (8.3 µg L-1) auf RC-2 (< 8.0 µg L-1) erforderlich. Eine detaillierte Optimierung der Prozessparameter der Setzmaschinentechnik könnten diesen Spielraum ermöglichen.
Die aus der Kirche in Greven entnommenen A. punctatum wiesen größere genetische Unterschiede auf als die aus der isolierten Zucht der BAM. Dies lässt vermuten, dass ein Austausch von zufliegenden oder eingeschleppten Individuen zu einer erhöhten genetischen Variabilität beiträgt.
Die Ergebnisse der Sequenzanalysen vom Standort Greven zeigten, dass vier Variationen vorhanden waren. Die DNA-Barcodes aus der Datenbank NCBI (Frankreich, Finnland und Deutschland) besaßen nur SNPs, die bereits aus den Insekten der Kirche in Greven bekannt waren. Nach aktueller Datenlage für den betrachteten Genabschnitt sind diese Varianten (V2 bis V22) als repräsentativ für den mitteleuropäischen Raum anzunehmen.
Potenzielle weitere Varianten lassen sich nur über eine größere Stichprobenanzahl entdecken/finden. Die Ergebnisse der Käferproben aus der isolierten Zucht der BAM sind deutlich homogener und entsprachen der Variante 1 aus Greven. Die Variante 1 wurde ebenfalls in vier französischen und einer deutschen Probe aus der NCBI-Datenbank nachgewiesen.
Die Ergebnisse deuten auf zwei Hauptvariationen (Vx und V20) hin, wobei die eine (VJ homogener als die andere (V20) zu sein scheint. Da für den Räuber K. caeruleus keine Unterschiede in der COI gefunden wurden, gilt zu prüfen, ob der gewählte Genabschnitt für die Untersuchung repräsentativ ist. Dies ist mit einer höheren Probenzahl zu validieren.
Following the recommendation of the European Chemicals Agency, on 25 September 2023 the European Commission passed a comprehensive new regulation to reduce emissions of microplastics (MP) into the environment, which includes the sale and use of intentionally added MP.1,2 This also applies to the application of synthetic rubber granulate infill in artificial turf systems and will ultimately have an impact on recreational sports. In Germany, rubber granulate made of ethylene-propylene-diene-monomer rubber (EPDM) is currently predominantly used. So far, there is no sufficient database for estimating MP emissions from artificial turf pitches into the environment and thus their relevance as a source of MP pollution.3 This topic is controversially discussed due to the complexity of sampling and analytics. To close this research gap, this project has the goal to determine mass balances for the emissions of MP from artificial turf pitches to allow an estimation of the amount of MP released per artificial turf pitch and year.
Within this study, MP emissions of three artificial turf scenarios at different time states (unaged, artificially aged and real-time aged) are compared: the past (old turf: fossil based, synthetic infill), present (most commonly installed in Europe: fossil based, EPDM infill), and the future (turf with recycled gras fibres, no synthetic infill). To simulate the outdoor weathering during the lifespan of an artificial turf of approx. 15 years, brand-new artificial turf and EPDM rubber granulate were accelerated aged by means of UV weathering and mechanical stress. Potential MP emissions into surface and groundwater are simulated by lysimeter and shake experiments. MP mass contents are subsequently determined by Thermal Extraction Desorption Gas Chromatography/Mass Spectrometry. Using special microfilter crucibles allows the estimation of the particle sizes of the emitted MP, which is a fundamental requirement for an assessment of potential health hazards for humans.
Microbiologically influenced corrosion (MIC) is a crucial issue for industry and infrastructure. Biofilms are known to form on different kinds of surfaces such as metal, concrete, and medical equipment. However, in some cases the effect of microorganisms on the material can be negative for the consistency and integrity of the material. Thus, to overcome the issues raised by MIC on a system, different physical, chemical, and biological strategies have been considered; all having their own advantages, limitations, and sometimes even unwanted disadvantages. Among all the methods, biocide treatments and antifouling coatings are more common for controlling MIC, though they face some challenges. They lack specificity for MIC microorganisms, leading to cross-resistance and requiring higher concentrations. Moreover, they pose environmental risks and harm non-target organisms. Hence, the demand for eco-friendly, long-term solutions is increasing as regulations tighten. Recently, attentions have been directed to the application of nanomaterials to mitigate or control MIC due to their significant antimicrobial efficiency and their potential for lower environmental risk compared to the conventional biocides or coatings. Use of nanomaterials to inhibit MIC is very new and there is a lack of literature review on this topic. To address this issue, we present a review of the nanomaterials examined as a biocide or in a form of a coating on a surface to mitigate MIC. This review will help consolidate the existing knowledge and research on the use of nanomaterials for MIC mitigation. It will further contribute to a better understanding of the potential applications and challenges associated with using nanomaterials for MIC prevention and control.
Im Rahmen eines vom Umweltbundesamt geförderten Forschungsprojekts wurde untersucht, ob die Abtrennung der Feinfraktion (0-2 mm) eine Verbesserung der umweltrelevanten Eigenschaften bewirkt und somit HMVA-1 erreicht werden kann. In Deutschland wird die Rostasche durch Nassentschlackungssysteme aus dem Feuerraum ausgetragen. Durch den Kontakt mit Wasser setzen direkt hydraulische Reaktionen ein, die eine vollständige Abtrennung der Feinfraktion unmöglich machen. Das wurde bereits in den 1990er Jahren erkannt und führte zur Entwicklung des ABB InRec Verfahrens mit Trockenentaschung als ersten Verfahrensschritt. Auch damals war das Ziel eine möglichst inerte Rostasche für die Verwertung zu erzeugen. In den letzten Jahren wurden in der Schweiz Trockenentaschungssystem installiert, hier vor allem um die Rückgewinnung von elementaren Metallen auch in der Feinfraktion zu verbessern. Welche Potenziale sich dabei erschließen lassen, wurde in einem anderen UBA-Projekt untersucht. Im Rahmen unserer Arbeiten wurde versuchsweise trockene Rostasche an einer Anlage in Süddeutschland genommen und im Labor untersucht. Im Vortrag werden die Ergebnisse zum Auslaugverhalten und zur Gefahreneigenschaft HP14 (Ökotoxizität) vorgestellt.
The use of ashes from municipal solid waste incineration as secondary building materials is an important pillar for the circular economy in Germany. However, leaching of potential toxic elements from these materials must be at environmentally acceptable levels. Normally, a three-month ageing period immobilizes most hazardous heavy metals, but antimony (Sb) and vanadium (V) showed previously unusual leaching. In order to clarify the mechanisms, we analyzed the Sb and V species in various bottom and fly ashes from municipal waste incineration by XANES spectroscopy. Antimony oxidizes from Sb(+ III) species used as flame retardants in plastics to Sb(+ V) compounds during waste incineration. However, owing to the similarity of different Sb(+ V) compound in the Sb K- and L-edge XANES spectra, it was not possible to accurately identify an exact Sb(+ V) species. Moreover, V is mainly present as oxidation state + V compound in the analyzed ashes. However, the coarse and magnetic fraction of the bottom ashes contain larger amounts of V(+ III) and V(+ IV) compounds which might enter the waste incineration from vanadium carbide containing steel tools. Thus, Sb and V could be critical potential toxic elements in secondary building materials and long-term monitoring of the release should be taken into account in the future.
Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios
(2024)
Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.
Volatile organic compounds (VOCs) emitted by furniture and building materials can cause health issues. For an improvement of indoor air quality low emitting materials should be used. Quality assurance and –control (QA/QC) measures require an emission reference material (ERM) with a predictable emission rate of VOCs. The idea is to use porous materials as ERM, which store the VOCs inside their pores and emit them constantly.