Phys.org reports on Princeton Engineering researchers who have found a way to turn egg whites into an aerogel that can then be used to filter lethal microplastic pollution from the oceans and our drinking water:
“I was sitting there, staring at the bread in my sandwich,” said [materials scientist Craig] Arnold. “And I thought to myself, this is exactly the kind of structure that we need.” So he asked his lab group to make different bread recipes mixed with carbon to see if they could recreate the aerogel structure he was looking for. None of them worked quite right initially, so the team kept eliminating ingredients as they tested, until eventually only egg whites remained.
“We started with a more complex system,” Arnold said, “and we just kept reducing, reducing, reducing, until we got down to the core of what it was. It was the proteins in the egg whites that were leading to the structures that we needed.”
Egg whites are a complex system of almost pure protein that—when freeze-dried and heated to 900 degrees Celsius in an environment without oxygen—create a structure of interconnected strands of carbon fibers and sheets of graphene. In a paper published Aug. 24 in Materials Today, Arnold and his coauthors showed that the resulting material can remove salt and microplastics from seawater with 98% and 99% efficiency, respectively.
“The egg whites even worked if they were fried on the stove first, or whipped,” said Sehmus Ozden, first author on the paper.
Because other proteins also worked, the material can potentially be produced in large quantities relatively cheaply and without impacting the food supply. One next step for the researchers, Ozden noted, is refining the fabrication process so it can be used in water purification on a larger scale.
If this challenge can be solved, the material has significant benefits because it is inexpensive to produce, energy-efficient to use and highly effective. “Activated carbon is one of the cheapest materials used for water purification. We compared our results with activated carbon, and it’s much better,” said Ozden.
You can read more of the team’s research here, in Materials Today.