kitNano-SCR – Development of nanoscale SCR catalysts for combined NOx and soot reduction in diesel engines
The Nano-SCR project was dedicated to developing diesel engine particulate filters provided with nanoscale catalysts for NOx reduction. In addition to stressing the requirement of manufacturing smallest possible catalysts, emphasis was placed on the systems’ aging resistance, the space- and weight-saving properties of the new generation of filter/catalyst systems, and an easier installation in diesel vehicles or systems for the after-treatment of exhausts.
Within the joint project Nano-SCR, NanoScape has developed and implemented novel nanoscale zeolite catalysts for reduction of nitrogen oxides (NOx, NO, NO2) from diesel exhausts. A novel catalyst which can be applied directly from aqueous suspensions in very thin layers to surfaces was manufactured upon development and charging of nanoscale zeolites with metal ions. The catalyst suspensions are scalable and can be produced without agglomeration. The SCR properties of these suspensions can be compared to those of standard catalysts. Besides, diverse metal ions can be integrated as early as in the liquid phase.
In the course of the project, NANO-X proved that aqueous coating systems with mixed oxides functioning as SRC catalysts on sinter metals provide good NOx conversion rates starting from 350°C and, in particular, from 450°C. Materials most active under Fast-SCR-conditions convert 50 percent of the nitrogen oxides at 350°C and 70 to 80 percent at 450°C. Doping with cerium oxide of <1mol percent cerium or mixed oxide causes significant improvement of the activity. The geometry of the sintered-metal substrate clearly affects the catalytic activity of mixed-oxide coatings that can be considerably influenced by the application and drying parameters of the coating solutions.
HJS had defined the performance specifications for coating suspensions, had coated porous sintered metal with the newly developed nano-suspensions and characterised the respective result, and had produced test filters to be tested on the engine test stand. Since the new nano-suspensions showed good adhesion with the metallic substrate, no catalyst particles are expected to be released during operation. Most engine test stand experiments were found to yield results comparable to the NOx reduction results of the synthesis gas test stand.
At TU Bergakademie Freiberg, a large number of SCR materials were screened within Nano-SCR. Besides, promising materials were comprehensively characterised and tested for their aging stability. Methods to enable a knowledge-based design of cerium oxide-containing catalysts were developed based on UV/VIS spectroscopy. Moreover, the mechanism of SCR reactions on nanoscale BEA zeolites was determined successfully by means of spectroscopic methods.
NanoMembrane – Nanoporous ceramic membranes for use in sustainable closed-cycle water- and solvent-saving methods
Within the NanoMembrane project, new ceramic nanofiltration membranes (NF) with reduced cut-offs and improved chemical stability were developed and tested in different applications. Whereas such testing served to check on the membranes’ stability and separation performance under conditions of use, it also provided clear definitions of the requirements to be met by membranes and hence contributed directly to optimising separation properties during development. The scientific/technical objectives comprised:
- Development of nanofiltration membranes with cut-offs of 200g/mol
- Development of pH-stable nanofiltration membranes
- Development of organophilic nanofiltration membranes
- Setup and adaptation of test facilities
- Laboratory and pilot tests with solvents and sewage from the chemical, textile, metal and paper industries
- Life cycle assessment/integrated life cycle assessment
Within the NanoMembrane project, ceramic nanofiltration membranes with cut-offs of approximately 200g/mol were synthesised for the first time at a specific water flow of 9 l/(m2•h•bar). The systematic assessment of the pH stability was carried out with two hours of filtration with hydrochloric acid and sodium hydroxide followed by a subsequent rinsing with water and determination of the retention with PEG-200 and revealed a stability of the NF-membranes in HCl of up to 2mol/l (7.2%) at 25°C and in NaOH of up to 4mol/l (16%) at 60°C. In organic solvent, the investigated NF-membranes, depending on the type of solvent used, showed very different, not yet describable behaviours. The best retentions were found to be achieved in THF with a cut-off of 350g/mol at a specific flow of 3,5 l/(m2•h•bar).
The fabrication of the novel ceramic NF-membranes was transferred from the laboratory (0.0055m2) to the technical scale (0.25m2). Ten different laboratory facilities and pilot plants for membrane characterisation and testing were used within the project. Besides, a filtration test plant for organic solvents was developed, set up and then used by Merck for pilot tests after approval by a relevant authority.
Application tests in the chemical, metalworking, textile finishing as well as paper and pulp industries confirmed the improved retention of dissolved molecules, dyes, surface-active agents, and multivalent salts as compared to previously used commercial membranes. The studies revealed approaches to an efficient and cost-effective use of membranes during the treatment of rinsing baths for cleaning metal parts and during preparation of bleaching solutions from pulp production.
Within integrated life cycle assessment, the use of ceramic nanofiltration membranes for treatment of liquid wastes or sewage proved to be of ecological benefit. Analysing concrete examples and attempting to generalise the different statements, basic know-how has been created which in the future will enable to draw up company- and application-specific life cycle assessments for use of ceramic nanofiltration membranes.
NanoKiesel – Nanoscale silica slurry – Technology developments on nanoscale silica slurry use in mineral building materials with the aim of improving material properties
Siliceous filter residues (FR) occur as wet filter cakes during treatment of sewage from the chemical industry. These residues are currently disposed of for a fee in landfills or are used for open pit backfilling. Due to their high content of amorphous silica and large specific surfaces, the filter residues have properties resembling those of micro-silica, a by-product of silica production which today is indispensable in the manufacturing of building materials.
This research project focused on investigating the use of two types of filter residues from different production processes in the building materials industry with the objective of improving certain properties. The filter residues were characterised extensively and their high amorphous silica contents were confirmed. The detected sulphate and chloride contents may limit the use of the residues.
Based on the results of characterisation, some feasible uses were preselected and verified experimentally:
- Pore-forming agents for brick production→ bulk density reduction through one of the investigated types of filter residues
- Concrete additive → increase in strength for both types of filter residues
- Constituent of composite concrete → increase in strength for both types of filter residues
- Special-render additive→ no effects confirmed
- Stabiliser for bentonite suspension→ impairment of properties
The technological conditions for using filter residues in the production of brick or concrete goods have been discussed. Comparative considerations on energy consumption and energy consumption costs identify the use of filter residues in bricks as being the least costly option.
UMSICHT – Assessment of the environmental hazards of silver nanomaterials: From chemical particles to technical products
The UMSICHT project was dedicated to obtaining a better understanding of the behaviour, fate, and impact of silver nanoparticles in the environment. Using standardised, optimised or newly developed procedures, the dissolution behaviour, transport behaviour, stability, and effects on living organisms in inshore waters and soils of differently manufactured particles were investigated under different conditions.
As an example of consumer products, silver nanoparticles in textiles were analysed investigating particle, fibre and fabric production through to abrasion and washing features and disposal in sewage treatment plants.
It became clear that the type of textile production decides on whether and in what quantities the particles get into the environment: In the ideal case, almost no and in the worst case almost all particles are being released. As silver nanoparticles are not completely retained in the sewage treatment plant, a small part may reach inshore waters, whereas the major part will end up in the soil through the usage of sewage sludge in agriculture.
The nanoparticles or the silver dissolved from them proved to be highly toxic for almost all investigated microorganisms. On the other hand, the quantities that finally end up in the environment are comparatively small. As silver cannot be degraded, however, it cannot be excluded that within decades to centuries, soil organisms will get damaged. This applies in particular to residues from imported products where neither the production method nor the amounts of contained silver nor the production quantities are known. It was found that the complexity of the product market is the major obstacle to reliable forecasts.
NAPASAN – Nanoparticles for groundwater damage repair
The NAPASAN project was dedicated to enhancing the processes of non-valent iron (nZVI) nanoparticles production regarding the selectivity of the pollutants to be removed and considering the relevant economic aspects. At the same time, the risks of using such nanoparticles for restoration of damage caused by groundwater were to be assessed, and proof was to be provided of the nanoparticles’ safe use regarding the success of restoration.
The following results were obtained within five interlinked work packages:
A new efficient method for production of non-valent iron (nZVI) nanoparticles through grinding of micro-iron was developed and was successfully tested on a large scale. Within the project, the new nZVI nanoparticles were characterised in detail and the production process and carrier suspension were optimised (UVR-FIA, KWI, TU Berlin, TZW, RWTH)
- Methods for incorporation and dispersion of nanoparticles in the subsoil were developed successfully and the feasibility of their practical implementation at the pilot site was verified (VEGAS, Kiel University, TU Berlin, TZW, IBL)
- To detect pollutants and iron nanoparticles (nZVI nanoparticles) in the aquifer, new monitoring arrays based on magnetic susceptibility measurement combined with micropumps were developed and tested both in the laboratory and at the pilot site (VEGAS, TU Berlin, Fugro, Hermes Messtechnik)
- Model-assisted site investigation based on direct-push technologies as well as models for dispersion of the iron nanoparticles (nZVI nanoparticles) in the soil were refined (CAU, Fugro)
A scientifically supported pilot application was planned and implemented successfully (VEGAS, IBL, Fugro)