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- Geosynthetics (3)
- Geotextiles (2)
- Marine littering (2)
- Artificial ageing (1)
- Bottom ash (1)
- CIS (1)
- CdTe (1)
- Cement-based composites (1)
- Chemical recycling (1)
- Chemisches Recycling (1)
Organisationseinheit der BAM
Mixed ionic electronic conducting ceramics Nd6-yWO12-d (d is the Oxygen deficiency) provide excellent stability in harsh environments containing strongly reactive gases such as CO2, CO, H2, H2O or H2S. Due to this chemical stability, they are promising and cost-efficient candidate materials for gas separation, catalytic membrane reactors and protonic ceramic fuel cell technologies. As in La6-yWO12-d, the ionic/electronic transport mechanism in Nd6-yWO12-d is expected to be largely controlled by the crystal structure, the conclusive determination of which is still lacking. This work presents a crystallographic study of Nd5.8WO12-d and molybdenum-substituted Nd5.7W0.75Mo0.25O12-d prepared by the citrate complexation route. High-resolution synchrotron and neutron powder diffraction data were used in combined Rietveld refinements to unravel the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d. Both investigated samples crystallize in a defect fluorite crystal structure with space group Fm3m and doubled unit-cell parameter due to cation ordering. Mo replacesWat bothWyckoff sites 4a and 48h and is evenly distributed, in contrast with La6-yWO12-d. X-ray absorption spectroscopy as a function of partial pressure pO2 in the near-edge regions excludes oxidation state changes of Nd (Nd3+) and W(W6+) in reducing conditions: the enhanced hydrogen permeation, i.e. ambipolar conduction, observed in Mo-substituted Nd6-yWO12-d is therefore explained by the higher Mo reducibility and the creation of additional – disordered – oxygen vacancies.
Almost 500 municipal solid waste incineration plants in the EU, Norway and Switzerland generate about 17.6 Mt/a of incinerator bottom ash (IBA). IBA contains minerals and metals. Metals are mostly separated and sold to the scrap market and minerals are either disposed of in landfills or utilised in the construction sector. Since there is no uniform regulation for IBA utilisation at EU level, countries developed own rules with varying requirements for utilisation. As a result from a cooperation network between European experts an up-to-date overview of documents regulating IBA utilisation is presented. Furthermore, this work highlights the different requirements that have to be considered. Overall, 51 different parameters for the total content and 36 different parameters for the emission by leaching are defined. An analysis of the defined parameter reveals that leaching parameters are significantly more to be considered compared to total content parameters. In order to assess the leaching behaviour nine different leaching tests, including batch tests, up-flow percolation tests and one diffusion test (monolithic materials) are in place.
A further discussion of leaching parameters showed that certain countries took over limit values initially defined for landfills for inert waste and adopted them for IBA utilisation. The overall utilisation rate of IBA in construction works is approximately 54 wt%. It is revealed that the rate of utilisation does not necessarily depend on how well regulated IBA utilisation is, but rather seems to be a result of political commitment for IBA recycling and economically interesting circumstances.
Das mechanische Recycling von Kunststoffen ist seit Jahren großtechnisch etabliert, hat aber technische und ökonomische Grenzen. Durch Verfahren des chemischen Recyclings gelangt man zurück zu Monomeren oder den Rohstoffen, so dass am Ende wieder Neuware für alle Einsatzgebiete von Kunststoffen entsteht. Die Vielfalt von chemischen Recyclingverfahren ist groß. Die Kapazitäten der Anlagen sind heute noch gering und die Wirtschaftlichkeit wird stark vom Ölpreis beeinflusst.
Die Rentabilitätsgrenze liegt derzeit bei einem Preis zwischen 50 und 60 US-$ pro Barrel.
Industrial-scale mechanical recycling of plastics has been established for years, but has technical and economic limits. Chemical recycling processes lead back to monomers or to the raw materials, so that in the end new goods can be produced for all areas of application of plastics. The variety of chemical recycling processes is large. The capacities of the plants are still low today. The profitability of the plants is strongly influenced by the price of oil; the profitability limit is currently between 50 and 60 US $ per barrel.
In 2011, the Association of German Engineers (VDI) started working on a set of guidelines
towards increased resource efficiency. These guidelines represent a framework that defines resource efficiency and outlines considerations for the producing industry. A special guideline for SMEs is included as well as guidelines on methodologies for evaluating resource use
indicators, such as the cumulative raw material demand of products and production systems.
Resource efficiency, defined here as the relationship between a specific benefit or use and the natural resources that need to be spent or consumed to attain this benefit or use. It can be
evaluated by defining a function which expresses the specific benefit and quantifies the resource requirements through a set of indicators (use of raw materials, energy, water, land
and ecosystem services including sinks). The results from this also depend on the system boundary parameters and the allocation rules for by-products and waste treatment options. Optimising resource use is possible at all stages of a product’s or production system’s life cycle chain (raw material extraction, production and manufacturing, use and consumption, and the
end-of-life stage).
VDI guidelines are widely accepted across Germany’s industrial sector and therefore represent an important means of mainstreaming resource efficiency in this target area. As well as providing a methodological framework, the guidelines describe strategies and measures towards increasing resource efficiency, and they enable industrial producers and service providers to identify potential areas of improvement. The full article presents an overview of
the methodology and contents of these guidelines and discusses their impact in achieving absolute reductions in the industrial use of natural resources.
Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80 °C and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years. Dynamic surface leaching and ecotoxicological tests were performed to determine the possible release of contaminants. No harmful effects on the test organisms were observed.
The database gives information on the contamination of the shore of the South-Eastern Baltic with the debris of geosynthetic materials for the period 2018–2020. This new type of coastal pollution enters the natural environment due to the destruction of coastal protection structures and construction activities. The database contains sections:
(1) a list of types of geosynthetic material residues, their photographic images and photographs illustrating examples of finds in natural conditions
[1 List_geosynthetic_debris_SEB],
(2) monitoring data on the contamination of the beach strip with the debris of geotextiles, braids from gabions, geocontainers (big bags), geocells and geogrids for the beaches of the South-Eastern Baltic for the period 2018–2020
[2 Monitoring_geosynthetic_debris_SEB];
(3) statistical distributions of the found geosynthetic debris by size
[3 Scales_geosynthetic_debris_SEB] and (4) results of test surveys on the shores of Lithuania and Poland adjacent to Kaliningrad Oblast.
All data refer to the beaches of the Kaliningrad Oblast (Russia), including the Russian parts of the Vistula and Curonian Spits, but also contains information on a one-time assessment of the pollution of the beaches of the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Materials were collected during field surveys within the ERANET-RUS_Plus joint project EI-GEO, ID 212 (RFBR 18-55-76002 ERA_a, BMBF 01DJ18005).
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.
The most massive design on the Baltic shore used geosynthetic materials, the landslide protection construction in Svetlogorsk (1300 m long, 90,000 m2 area, South-Eastern Baltic, Kaliningrad Oblast, Russian Federation) comprises the geotextile and the erosion control geomat coating the open-air cliff slopes. Due to changes in elastic properties during long-term use in the open air, as well as due to its huge size, this structure can become a non-negligible source of microplastic pollution in the Baltic Sea. Weather conditions affected the functioning of the structure, so it was assessed that geosynthetic materials used in this outdoor (open-air) operation in coastal protection structures degraded over time. Samples taken at points with different ambient conditions (groundwater outlet; arid places; exposure to the direct sun; grass cover; under landslide) were tested on crystallinity and strain at break. Tests showed a 39–85% loss of elasticity of the polymer filaments after 3 years of use under natural conditions. Specimens exposed to sunlight are less elastic and more prone to fail, but not as much as samples taken from shaded areas in the grass and under the landslide, which were the most brittle.
Many organizations in Europe collect data and perform research on municipal solid waste and the secondary raw materials that can be produced from them through recycling, urban mining, or landfill mining.However, the information generated and presented thereby is often highly aggregated, while research activities are many a time isolated. Both reduce the usability of the data and information generated. In order to better structure the knowledge generation on secondary raw materials production from municipal solid waste, we suggest to learn from the traditional raw materials mining Industry how to perform an integrated assessment and reporting of anthropogenic resources. This is exemplarily shown for the case of the anthropogenic resource municipal solid waste incineration bottom ash and airpollution control residues. A network of expert institutions from countries throughout Europe was build up to compile the information on legal and technological aspects for the recovery of different secondary raw materials from these residues, including construction minerals, metals, and salts. We highlight in our article the strength of the combined knowledge of an expert network not only on legal and technological, but also local and site-specific aspects of the recovery of secondary raw materials. By doing so, we hope to kick-off a discussion for how to organize and implement a structure for a better management of knowledge on anthropogenic resources, in order to provide a sustainable supply of secondary raw materials for a greener and more circular economy.