COLUMBUS , Ohio -- Engineers at Ohio State University have found a way to turn discarded chicken eggshells into an alternative energy resource.
The patented process uses eggshells to soak up carbon dioxide from a reaction that produces hydrogen fuel. It also includes a unique method for peeling the collagen-containing membrane from the inside of the shells, so that the collagen can be used commercially.
L.S. Fan, Distinguished University Professor of chemical and biomolecular engineering at Ohio State, said that he and former Ohio State doctoral student, Mahesh Iyer, hit upon 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 eggshell plays a critical role.
"The key to making pure hydrogen is separating out the carbon dioxide," Fan said. "In order to do it very economically, we needed a new way of thinking, a new process scheme."
That brought them to eggshells, which mostly consist of calcium carbonate -- one of nature's most absorbent materials. It is a common ingredient in calcium supplements and antacids. With heat processing, calcium carbonate becomes calcium oxide, which will then absorb any acidic gas, such as carbon dioxide.
In the laboratory, Fan and his colleagues demonstrated that ground-up eggshells could be used in the water-gas-shift reaction. Iyer performed those early experiments; recent graduate Theresa Vonder Haar also worked on the project for her bachelor's degree honors thesis.
Calcium carbonate - a key ingredient in the eggshells -- captures 78 percent of carbon dioxide by weight, Fan explained. That means, given equal amounts of carbon dioxide and eggshell, the eggshell would absorb 78 percent of the carbon dioxide.
That makes it the most effect
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Ohio State University