Oil into the Ozean?
Damages from ships or oil rigs, where there is an oil spill, are always present. Researchers are therefore looking for new ideas on how to eliminate the leaked oil - for example with the aid of highly porous materials. This works also in principle, but unfortunately not to the hoped-for extent.
"So now!"
Dübendorf in Switzerland. A small workshop.
"It's very noisy, and you have to imagine that as a puree bar."
Welcome to the laboratory for the purpose of using kitchen machines! Because this is not potato purée produced.
The next station: a large stainless steel mill.
"For example, to grind vegetables or grind fruits."
But even this does not happen here!
"After the mill, we make a sorbet with this ice machine. A sorbet is an ice-cream, which is water-based, where you do not have milk, but has only water and the fruit mix."
Cellulose fibers with widely branched cavities
Only: No one would like to try this sorbet!
"It does not taste like anything!"
What is pureed, ground, watered and frozen at the end are not food. This is a laboratory for applied wood research. At EMPA, the Swiss state center for material research. The woodworker Tanja Zimmermann and the chemist Thomas Geiger bow over a steel tunic:
"This milky, gel-like mass, that is cellulose fibers, as is known from the pulp industry, which form the starting material for paper making, which is now floating in the water."
Three years ago, the researchers began working with the wood framework, together with colleagues from ETH Zurich. Their goal at the time was extremely absorbent cellulose sponges with wide-bodied cavities which absorb large amounts of oil, for example, after a ship's bayry. "Nanoschwammen against the oil spill" - thus the EMPA described the project crisply as it started.
"You could throw that into the water, yes, as a cube or as a plate, and then you have to imagine the whole thing like a styrofoam plate, looks like styrofoam."
Porosity of over 99 percent
The microfibrillated cellulose, as it is called, can absorb a multiple of its own weight. Thomas Geiger presents a small sample cube at the Chemistry Laboratory. Mass?
"About 25 grams when he has sucked the oil, and if he has not sucked in oil, he weighs in, two grams."
So that the dice also only swallow oil, it is coated with silanes. These are water-repellent compounds. They are also referred to as hydrophobing agents:
"We immerse the solution into the solution, moisten it on all sides with the hydrophobing agent, then get it out again, let it dry again, and then the product is ready and can absorb oil The oil is filled with very thin channels, and this physical force that occurs in the process holds the oil And that's called capillary force. "
Sponges probably too light for rough seas
In principle this works as well. However, the suction power of the wood fiber sponges is not enough for a real oil spill at sea, as Tanja Zimmermann admits:
"We're not yet ready for our records to be a good thing for crude oil, which runs out in the sea, so I guess we'd use it on smaller motorboat accidents on Lake Zurich Oil, and you would then take this plate or take these dice and then soak up this oil puddle. "
A pool made of comparatively light engine oils. When a tanker accidentally kills or kills an oil rig, heavy fuel flows into the sea:
"This is much, much thicker, even more sticky, and there is the question how well this could be re-incorporated into the structure by the capillary forces."
And something else speaks for Thomas Geiger rather against the use in oil accidents in the ocean:
"The sea, which is rough, when there is wind, there are waves, our material is very light, which could fly away."
Research project runs for another year
However, there is still the chance that the suction sponges will create a market product. EMPA and ETH Zurich are cooperating with a Swiss fiber producer in their project, and they are still testing the material extensively. One idea, for example, is to put the cellulose cubes in tissue tubing. This would lead to new oil barriers for lakes or streams, "so that when the oil rug now comes, it will hang in the oil barrier, then pass through the fabric, into the foams, and the foams suck that And then you can get the oil barrique. "
The joint project runs for another year, says Tanja Zimmermann:
"And then the company has to decide whether it's really going to work, and then of course we are very confident that there are also products on the market."
Others are already further. For example the company Deurex in Saxony-Anhalt. Her managing director, a chemist, has just received the European Inventory Prize. For a cotton wool, which also floats on the water, binds oil - if not as much as the Swiss cellulose - and is already marketed. It has proved successful in cases of fuel oil leaking in the Elbe. But offshore accidents? They would surely be too big for the cotton wool.