Eggshell absorbers

Engineers at Ohio State University have found a novel use for discarded chicken eggshells. The patented process that they have developed uses eggshells to soak up carbon dioxide from a reaction that produces hydrogen fuel.

L.S. Fan, Prof 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 key to making pure hydrogen is separating out the carbon dioxide,’ Fan said. ‘To do it very economically, we needed a new way of thinking, a new process scheme.’

That brought them to the eggshells, which mostly consist of calcium carbonate - one of nature’s most absorbent materials. With heat processing, calcium carbonate becomes calcium oxide, which will then absorb any acidic gas, such as carbon dioxide.