Tuesday, April 16, 2024

Egg-based aerogel can cheaply remove microplastics from seawater

Microplastics from seawater have a devastating impact on the marine environment. Also, it often makes its way into edible salts, making the salts potentially harmful to human health.

Researchers at Princeton Engineering have used egg whites to create an aerogel, a lightweight and porous material that can cheaply remove salt and microplastics from seawater. The material can be used in many types of applications, including water filtration, energy storage, and sound and thermal insulation.

Craig Arnold, the Susan Dod Brown Professor of Mechanical and Aerospace Engineering and vice dean of innovation at Princeton, came up with the idea while sitting in a faculty meeting.

When freeze-dried and heated, the egg whites to 900 degrees Celsius in an oxygen-free environment, their pure protein system creates a structure of interconnected strands of carbon fibers and sheets of graphene. The resulting material can remove salt and microplastics from seawater with 98% and 99% efficiency, respectively.

The structure of the aerogel is formed by graphene sheets stretched across carbon fiber networks.
The structure of the aerogel is formed by graphene sheets stretched across carbon fiber networks. Credit: Shaharyar Wani

The material has significant benefits because it is inexpensive to produce, energy-efficient to use, and highly effective. This filtration process requires only gravity to operate and won’t consume energy or excess water. Activated carbon is one of the cheapest materials used for water purification, but it is not nearly as effective as egg-based aerogel.

Because other proteins also work, aerogel can potentially be produced in large qualities relatively cheaply and without impacting the food supply. Researchers are next planning to refine the fabrication process so it can be used in water purification on a larger scale.

Arnold sees water purity as a “major grand challenge” that is not the only potential application for this material. He is also exploring other uses related to energy storage and insulation.

Journal reference:

  1. Sehmus Ozden, Susanna Monti, Valentina Tozzini, Nikita S. Dutta, Stefania Gili, Nick Caggiano, A. James Link, Nicola M. Pugno, John Higgins, Rodney D. Priestley, Craig B. Arnold. Egg protein-derived ultralightweight hybrid monolithic aerogel for water purification. Materials Today, 2022; DOI: 10.1016/j.mattod.2022.08.001