As Princeton’s vice dean for innovation and the Susan Dod Brown Professor of Mechanical and Aerospace Engineering, Craig Arnold collaborates with his lab to develop new materials, such as aerogels, for use in engineering.
He got the idea one day while attending a faculty meeting.
“I was sitting there staring at the bread in my sandwich,” said Arnold. “And I thought to myself, this is exactly the kind of structure we need.” So he asked his lab team to make different bread recipes mixed with charcoal to see if they could recreate the airgel structure he was looking for. None of them worked quite right at first, so the team kept removing ingredients during testing until finally all that was left were egg whites.
“We started with a more complex system,” Arnold said, “and kept reducing, reducing, reducing until we got to the core of what it was. The proteins in the egg whites led to the structures we needed.”
When freeze-dried and heated to 900 degrees Celsius in an oxygen-free atmosphere, egg whites, a complex system of nearly pure protein, form a structure of intertwined carbon fibers and graphene sheets. Arnold and his co-authors demonstrated the final material’s effectiveness in removing salt and microplastics from seawater in a paper published Aug. 24 in the journal Materials Today.
“Egg whites will work even if they are first fried on the stove or beaten,” said Sehmus Ozden, first author of the paper. Ozden is a former postdoctoral researcher at the Princeton Center for Complex Materials and is now a researcher at the Aramco Research Center. Although initial tests used standard store-bought egg whites, Ozden said other similar commercially available proteins produced the same results.
“Eggs are cool because we can all connect with them and they’re easy to get, but you have to be careful about competing against the food cycle,” Arnold said. Since other proteins also work, the material can potentially be produced in large quantities relatively cheaply and without affecting food intake. One next step for the researchers, Ozden noted, is to refine the manufacturing process so it can be used for water purification on a larger scale.
The material has considerable advantages if this problem can be solved, as it is cheap to manufacture, energy efficient to use and highly efficient. One of the cheapest materials used in water treatment is activated carbon. According to Ozden, our results are much better compared to activated carbon. This filtration technology uses only gravity and does not waste water, unlike reverse osmosis, which operates with significant energy consumption and excess water.
While Arnold sees water purity as a “huge big problem,” there are other potential uses for this substance. He is also researching other applications for insulation and energy storage.
Source: The Nordic Page