Crackpot idea or recipe for success? This is a question entrepreneurs often face. Is it worth converting the production process to a new, ecologically better material? Empa has developed an analysis method that enables companies to simulate possible scenarios – and therefore avoid bad investments. Here’s an example: Nanofibers made of carrot waste from the production of carrot juice, which can be used to reinforce synthetic parts. Motorcycle helmets consist of fiber-reinforced synthetic material. Instead of glass fibers, a biological alternative is now also possible: plant fibers from the production of carrot juice. Empa researchers are now able to analyze whether this kind of production makes sense from an ecological and economical perspective – before money is actually invested in production plants. All over the world, research is being conducted into biodegradable and recyclable synthetics. However, fiber-reinforced components remain problematic – if glass or carbon fibers are used. Within the scope of an EU research project, the Scottish company Cellucomp Limited has now developed a method to obtain nanofibers from carrot waste. These fibers would be both cost-effective and biodegradable. However, is the method, which works in the lab, also marketable on a large scale? An MPAS (multi-perspective application selection) method developed at Empa helps identify the industrial sectors where new materials might be useful from a technical and economical perspective. At the same time, MPAS also considers the ecological aspect of these new materials. The result for our example: Nanofibers made of carrot waste might be used in the production of motorcycle helmets or side walls for motorhomes in the future. Three-step analysis In order to clarify a new material’s market potential, Empa researchers Fabiano Piccinno, Roland Hischier and Claudia Som proceed in three steps for the MPAS method (, "Multi-perspective application selection: a method to identify sustainable applications for new materials using the example of cellulose nanofiber reinforced composites"). First of all, the field of possible applications is defined: Which applications come into question based on the technical properties and what categories can they be divided into? Can the new material replace an existing one? The second step concerns the technical feasibility and market potential: Can the material properties required be achieved with the technical process? Might the product quality vary from one production batch to the next? Can the lab process be upgraded to an industrial scale cost-effectively? Is the material more suited to the low-cost sector or expensive luxury goods? And finally: Does the product meet the legal standards and the customers’ certification needs? In the third step, the ecological aspect is eventually examined: Is this new material for the products identified really more environmentally friendly – once all the steps from product creation to recycling have been factored in? Which factors particularly need to be considered during production stage to manufacture the material in as environmentally friendly a way as possible? Industrial production on a five-ton scale – calculated theoretically The MPAS approach enables individual scenarios for a future production to be calculated with an extremely high degree of accuracy. In the case of the carrot waste nanofibers, for instance, it is crucial whether five tons of fresh carrots or only 209 kilograms of carrot waste (fiber waste from the juicing process) are used as the base material for their production. The issue of whether the solvent is ultimately recycled or burned affects the production costs. And the energy balance depends on how the enzymes that loosen the fibers from the carrots are deactivated. In the lab, this takes place via heat; for production on an industrial level, the use of bleaching agents would be more cost-effective. Conclusion: six possible applications for “carrot fibers“ For fiber production from carrot waste, the MPAS analysis identified six possible customer segments for the Scottish manufacturer Cellucomp that are worth taking a closer look at: Protective equipment and devices for recreational sport, special vehicles, furniture, luxury consumer goods and industrial manufacturing. The researchers listed the following examples: Motorcycle helmets and surfboards, side walls for motorhomes, dining tables, high-end loudspeaker boxes and product protection mats for marble-working businesses. Similarly detailed analyses can also be conducted for other renewable materials – before a lot of money is actually invested in production plants.
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Pouring fire on fuels at the nanoscale
There are no magic bullets for global energy needs. But fuel cells in which electrical energy is harnessed directly from live, self-sustaining chemical reactions promise cheaper alternatives to fossil fuels. To facilitate faster energy conversion in these cells, scientists disperse nanoparticles made from special metals called ‘noble’ metals, for example gold, silver and platinum along the surface of an electrode. These metals are not as chemically responsive as other metals at the macroscale but their atoms become more responsive at the nanoscale. Nanoparticles made from these metals act as a catalyst, enhancing the rate of the necessary chemical reaction that liberates electrons from the fuel. While the nanoparticles are being sputtered onto the electrode they squash together like putty, forming larger clusters. This compacting tendency, called sintering, reduces the overall surface area available to molecules of the fuel to interact with the catalytic nanoparticles, thus preventing them from realizing their full potential in these fuel cells. Electron Microscopy image depicting the Palladium- Magnesium Oxide core-shell combination. The white dots are Palladium nanoparticles. The slight haze around each nanoparticle is the porous magnesium oxide shell. The Palladium nanoparticles are not sintered together and maintain spaces between each another because of these shells. This maximizes their ability to react with chemicals. (Image: OIST) Research by the Nanoparticles by Design Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), in collaboration with the SLAC National Laboratory in the USA and the Austrian Centre for Electron Microscopy and Nanoanalysis, has developed a way to prevent noble metal nanoparticles from compacting, by encapsulating them individually inside a porous shell made of a metal oxide. The OIST researchers published their findings in ("Engineering high-performance Pd core–MgO porous shell nanocatalysts via heterogeneous gas-phase synthesis"). Their work has immediate applications in the field of nano-catalysis for the manufacturing of more efficient fuel cells. The OIST researchers designed a novel system. They encapsulated Palladium nanoparticles in a shell of Magnesium oxide. Then they dispersed this core-shell combination on an electrode and measured the immersed electrode’s abilities in improving the rate of the electrochemical reaction that occurs in methanol fuel cells. They demonstrated that encapsulated Palladium nanoparticles give a significantly superior performance than bare Palladium nanoparticles. The OIST researchers had previously realized that Magnesium oxide nanoparticles could form porous shells around noble metal nanoparticles while studying Magnesium and Palladium nanoparticles separately. The porosity of this added armor ensures it does not screen molecules of the fuel from reaching the encapsulated Palladium. Electron microscopy images confirmed that the Magnesium oxide shell simply acts as a spacer between the Palladium cores as they try to stick to each other, letting each to realize its full reactive potential. The advanced nanoparticle deposition system at OIST allowed the researchers to fine tune the experimental parameters and vary the thickness of the encapsulating shell as well as the number of Palladium nanoparticles in the core with relative ease. Tuning sizes and structures of nanoparticles alters their physical and chemical properties for different applications. “More core-shell combinations can be tried using our technique, with metals cheaper than Palladium for instance, like Nickel or Iron. Our results show enough promise to continue in this new direction,” said Vidyadhar Singh, the paper’s first author, and postdoctoral fellow under the supervision of Prof. Mukhles Sowwan, the director of OIST’s Nanoparticles by Design Unit, who was also a corresponding author of the paper.
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