Scientists say they have found a way to use discarded eggshells to help make hydrogen fuel.

Engineers at Ohio State University announced Wednesday that they have come up with a patented process to use chicken eggshells to soak up carbon dioxide from a reaction that produces hydrogen fuel. As a bonus, the process includes a unique method for peeling the collagen-containing membrane from the inside of the shells, allowing the collagen to be used commercially.

Engineers at Ohio State University say they have found a way to use discarded eggshells to help make hydrogen fuel.

Chemical and biomolecular engineer L.S. Fan and former doctoral student Mahesh Iyer, came up with the idea when they were trying to improve a method of hydrogen production called the water-gas-shift reaction. With this method, fossil fuels such as coal are gasified to produce carbon monoxide gas, which then combines with water to produce carbon dioxide and hydrogen.

The eggshells soak up the carbon dioxide, leaving behind pure hydrogen, which can then be used as fuel. Energy experts believe that hydrogen may become an important power source in the future, most notably in the form of fuel cells. But first, researchers must develop affordable ways to produce large quantities of hydrogen.

The process works because eggshells are mostly made up of calcium carbonate — a very absorbent material. Calcium carbonate is a common ingredient in calcium supplements and antacids. When calcium carbonate is heated, it becomes calcium oxide, which will then absorb acidic gas such as carbon dioxide.

Calcium carbonate captures 78 per cent of carbon dioxide by weight, said Fan. That means given equal amounts of carbon dioxide and eggshell, the eggshell absorbs 78 per cent of the carbon dioxide.

But since the eggshells must be ground up for the process to work, the engineers first needed to remove the collagen-containing membrane that clings to the inside.

By developing an organic acid that strips the membrane from the shell, they were able to isolate a marketable form of collagen, which sells for about $1,000 US a gram.

Collagen is used in food, pharmaceuticals and medical treatments. Doctors use collagen to help burn victims regenerate skin and to perform cosmetic surgery.

"We like that our technology can help the egg industry to dispose of its waste, and at the same time convert the waste to a useful product," Fan said in a news release.