Princeton Engineering researchers have discovered a way to turn your breakfast (Egg white to create aerogel) cereal into a new ingredient that can cheaply remove salt and microplastics from water.
Researchers are using egg white to create aerogel, a lightweight material that can be used in many applications, including water filtration, energy storage, and sound and heat insulation. Craig Arnold, Susan Dod Brown Professor of Mechanical and Aerospace Engineering, Vice Dean of Innovation at Princeton and Executive Committee Member of the Andlinger Center for Energy and Environment, works in his laboratory to develop new materials, including aerogels, for engineering applications .
One day, sitting in a department meeting, he had an idea. “I was sitting there looking at the bread on my sandwich,” Arnold said. “I thought to myself, this is exactly the kind of arrangement we need.” So he asked his lab team to make a carbon-based cake recipe to see if they could recreate the atmosphere he was looking for. None of them worked well at first, so the team kept clearing out the ingredients as they experimented, until later, it was just white eggs remaining.
“We started with a complex process, and we kept reducing, reducing, reducing, until we got to the core of what it was,” Arnold said. It is the proteins in the egg that make the things we need.
Egg whites are a complex system of almost pure protein that, after being dried and heated at 900 degrees Celsius in an oxygen environment, creates a structure of carbon fibers and sheets of graphene bonded together. In an article published in August. 24 in Materials Today, Arnold and his co-authors showed that the resulting product can remove salt and microplastics from water with 98% and 99% efficiency, respectively.
“Egg whites work even if they are fried on the stove or beaten first,” said Sehmus Ozden, first author of the book. Ozden is a former postdoctoral researcher at the Princeton Center for Complex Materials and currently a scientist at the Aramco Research Center. Although store-bought egg whites were used in the first test, Ozden said, other commercially available proteins produced the same results.
“Treasures are great because we can all connect to them and they’re easy to access, but you have to be careful not to compete with the food system,” Arnold said. Because other proteins have also worked, the material can be produced in large quantities at high cost without affecting nutrition. The next step for the researchers, Ozden said, is to refine the manufacturing process so it can be used to purify water on a large scale.
If this challenge can be solved, the property has great value because it is inexpensive to create, effective to use, and efficient. “Activated carbon is one of the cheapest materials used to purify water. We compared our results with activated charcoal, and it’s much better,” said Ozden. Compared to reverse osmosis, which requires a large amount of energy and water to operate, this filter system only requires energy. gravity to work and not waste any water.
Although Arnold sees the purity of water as a “big challenge”, that is not the only potential application for this. It also explores other uses related to energy storage and insulation.
