Look at a chicken feather, and what you’re seeing is 91% keratin. Now a team of scientists have found a way to repurpose this abundant agricultural byproduct—and in a surprise move, they’ve used it to make renewable energy.
The scale of the global poultry industry is such that it produces 6 billion tons of chicken feathers each year, most of which are tossed aside. The problem isn’t just the waste, but the impact it goes on to have: an estimated 40 million tons of these waste feathers are burned annually, spewing out sulfur dioxide and carbon dioxide in the process.
Meanwhile, keratin is actually an incredible useful ingredient in so many industries, from medicine to packaging. But the researchers on the new study set their targets on green energy for the wasted feather flurry.
They had their eye on a crucial component of hydrogen fuel cells that sorely needs an upgrade. Hydrogen fuel cells generate electricity by combining hydrogen with oxygen atoms, and produce a clean electrochemical reaction, instead of combustion. Key to this process is the cell’s semi-permeable membrane, across which protons can move to generate the required chemical reaction. However, “normal fuel cell membranes are formed by highly toxic polymers which cannot be degraded, and which persist in the environment,” says the paper’s lead author Raffaele Mezzenga, who is a materials scientist at the Swiss Federal Institute of Technology, Zurich.
However, permeable keratin brings the possibility of a non-toxic alternative. First, Mezzenga and team set about isolating the keratin from chicken feathers using an environmentally-friendly process, then applying a heat treatment to transform the ingredient into fibrils.
Crucially, these threadlike strands of protein molecules are incredibly resilient under conditions like the high temperatures of a fuel cell, and so made robust building blocks. The fibrils were then mixed with other ingredients to enhance their electrical conductivity, then dried and fashioned into a flat membrane. Finally, this was incorporated into the design of a commercial hydrogen fuel cell.
When the researchers tested it out, it was a feather-fuelled success: the fuel cell was able to convert hydrogen and oxygen into electricity, with proof in the fact that it powered two LED lamps. In further testing, it drove a motor-powered fan and a toy car. Aside from electricity, the fuel cell’s only byproduct was water.
Mezzenga says he’s excited about “the clear demonstration that food waste, currently ending up in incineration or in the very best scenario—some sort of animal feed, can be converted into membranes for the generation of clean electric energy.”
The energy the feather membrane created was not only comparable to that of traditional fuel cells, but cost less than half as much to produce, and without the usual environmental impact, the researchers found. “We start from side streams which are typically burned (generating CO2), and instead of contributing to CO2 emissions, we use them for production of energy at zero carbon footprint,” Mezzenga explains. “The overall carbon balance is therefore obviously negative.”
This no-emissions alternative to incineration could help to scale back agriculture’s considerable emissions impact, while powering the transition to clean energy—quite an impressive pair of accomplishments for the humble and unloved chicken feather.
Mezzenga and team are now enthusiastically focused on bringing their inventive membrane tech into the mainstream. “We plan to convert this laboratory proof-of-concept into a profitable technology, capable of yielding clean energy while preserving the environment,” he says. “We are convinced this can be done at an industrial scale.”
Mezzenga et. al. “Renewable Energy from Livestock Waste Valorization: Amyloid-Based Feather Keratin Fuel Cells.” ACS Applied Materials & Interfaces. 2023.
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