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A damaging action of HNO3-55% only occurs in combination with its decomposition into nitrous gases, which can be caused by UV radiation. In a laboratory test, transparent HDPE jerrycans have been exposed to both UV radiation and 55 wt-% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The respective damages are compared with FTIR spectroscopy in ATR and HT-gel permeation chromatography (GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. The gradual increase in oxidative damage shows the good reproducibility of the lab exposure. The decomposition of nitric acid into nitrous gases by UV radiation – as well as the jerrycan oxidation – is also observed at lower HNO3 concentration (28 wt- %). Similar results are obtained after outdoor tests. Again, the damage occurs only after combined exposure, in contrast to the exposures to UV only and to HNO3 only, which were conducted in parallel. Outdoor exposures are most readily accepted as they represent possible end-use conditions. However, the reproducibility of these exposures is poor due to the large temporal variations in weather. There are also several safety risks, which is why the number of replicates remains limited. Since the outdoor and lab exposure tests show the same qualitative results, it is appropriate to conduct systematic studies in the laboratory. After 6 days of lab exposure, the oxidation damage is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. It should be noted that this amount can also occur in two sunny weeks.
Nanomaterials are present in our everyday life. Paint coats, sunscreens, catalysts and additives for tyres are good examples for the use of such materials in mass-market products. The problem of the safety of nanomaterials is recognized as a problem for health and environment, which lead to the special registration of nanomaterials according to an annex of REACH as of 2020. But a great problem for the risk assessment of nanomaterials that several factors could influence the hazardous nature of them. Additional to composition, crystal structure, size and shape the surface properties of such particles belong to these parameters for risk assesment. The reason for the relevance of the surface is obvious: the smaller the particle, the higher is the share of the surface. Additionally, the surface is the region of the particle which interacts with the surrounding which is another crucial factor for the understanding the effect of a nanomaterial on health and environment. In the OECD Testing Programme on Manufactured Nanomaterials exists consequently an Endpoint 4.30 Surface Chemistry in Chapter 4. PHYSICAL AND CHEMICAL PROPERTIES. In summary, there is obviously a need for a correlation between surface chemical analytic data and toxicity. To fill in this gap, we present surface analytic results obtained with X-ray photoelectron spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry and correlate them with cytotoxic data gain by high-throughput screening experiments. It must be noted, that these experiments were done at the same set of titania materials taken from the JRC (Joint Research Centre of the European Union) Nanomaterials Repository. As material TiO2 was chosen due to its widespread use in consumer products, e.g. paint coats and sunscreens. With this new approach a better understanding of the influence of surface properties on the toxicity can be expected leading to a better risk assessment of these materials.
Biodiesel (FAME) from rapeseed is an environmentally friendly alternative to common fossil fuels. It is also suitable to serve as blending component to fuels like heating oil. If the fuel composition is changed, materials compatibility must be guaranteed. Adding polar biodiesel to nonpolar heating oil, changes the blend’s solvency and might cause swelling, extraction and solvation of polymers.
The objective of this research was to investigate the compatibility of polymeric materials, which are commonly used for components in middle distillate facilities, along with blends of heating oil and 20 % biodiesel (B20). For this propose, ACM, HNBR, FKM, PE, PA 6, POM, PUR and PVC were exposed to heating oil and B20 for 42 and 84 days at 40 °C. In addition, the polymers HNBR, FKM, PA, POM and PVC were also exposed at 70 °C. Furthermore, the resistance of polymers in eight-year aged B10 at 40 °C was evaluated. Ageing of biodiesel increases acidity which might propagate polymer corrosion.
The materials were evaluated as resistant, if the loss in tensile properties (tensile strength and elongation at break) and Shore hardness remained under 15 % compared to the initial unexposed material values. For investigations under compressed conditions, the compression set was determined for specimens of ACM, FKM and HNBR after exposure in heating oil B0 and B20 for 3,7,14, 28, 56 and 90 days at 40 °C according to ISO 815-1.
It was found that the resistance in B20 at 40 °C was given for all tested polymers except PUR. In the 8 years aged B10, PUR and POM were not compatible and ACM just conditionally compatible. At 70 °C, FKM and PVC were resistant in B20, whereas HNBR and PA 6 were not compatible. Swelling occurred for the elastomers ACM, HNBR and PUR.
The exposure to antimicrobial substances drives the evolution of antimicrobial resistance. Biocides are antimicrobials used as disinfectants, antiseptics and preservatives. They find application on a large scale in the industrial and medical sector, but also in private households. In terms of mass, the worldwide use of biocides exceeds that of antibiotics. Thus, despite their important role in preventing the spread of pathogens, due to their ubiquity, biocides are suspected to be drivers of the antimicrobial resistance crisis. In our work at BAM we try to understand how biocides contribute to the emergence of AMR, what the underlying adaptation principles and mechanisms are and how they compare to those found for antibiotics. Within our group, I mainly focus on the following two questions: How does phenotypic heterogeneity in bacteria affect the ability to survive treatment with biocides? And what are the consequences of phenotypic heterogeneity for the evolution of resistance to biocides and antibiotics?
I will share published and unpublished results which demonstrate that phenotypic heterogeneity can enable the survival of biocide treatment and, through this, facilitate the evolution of AMR. On the other hand, we find that adaptation to a biocide can unexpectedly impair the ability to evolve resistance against an antibiotic.
The presentation gives an overview about the use of ecotoxicity testing in assessment of waste. Especially in cases with unknown composition this kind of test are useful. Recently, the assessment of the hazard property HP 14 "ecotoxicity" for the labelling of waste was published. The labelling procedure is explained in detail.
The presentation gives an overview about the use of ecotoxicity testing in assessment of waste. Especially in cases with unknown composition this kind of test are useful. Recently, the assessment of the hazard property HP 14 "ecotoxicity" for the labelling of waste was published. The labelling procedure is explained in detail.
The presentation gives an overview about the use of ecotoxicity testing in assessment of waste. Especially in cases with unknown composition this kind of test are useful. Recently, the assessment of the hazard property HP 14 "ecotoxicity" for the labelling of waste was published. The labelling procedure is explained in detail.
Commercially available carbon steels are suitable for compression and pipelines as long as moisture content and impurities are limited. (water 50 to 100 ppmv, SO2 and NO2 ca. 100 ppmv) Corrosion rates increase with increasing water content. (0.2 – 20 mm/a) Condensation of acids and therefore droplet formation is always possible, even at low water contents. A low SO2 content within the CO2-stream might be more important than a low water content. Cr13-steels showed a general susceptibility to shallow pitting and pitting. So, they seem to be not suitable for CCUS applications. Low alloyed steels showed better corrosion behavior (predictable uniform corrosion). For direct contact with saline aquifer fluids only high alloyed steels shall be used.