Eggshells could be used to fight global warming
By Darren Quick
October 29, 2010
Carbon capture and sequestration (CCS) is a hot area of research in the effort to fight global warming through the process of removing carbon from the atmosphere and ferreting it away within carbon soaking materials, a team from the University of Calcutta has found an unexpected (or should that be uneggspected) material that could trap carbon from the atmosphere in the form of eggshells. The team has demonstrated that the membrane that lines an eggshell can absorb almost seven times its own weight of carbon dioxide from the atmosphere, allowing the gas to be stored until environmentally friendly methods of disposing, or even using it, can be found.
The team explains that eggshell comprises three layers; a cuticle on the outer surface, and a spongy calcium-containing middle layer and inner layer. The second and third layers are composed of protein fibers bonded to calcium carbonate – a chemical compound that results from another carbon sequestration technology also developed in India using naturally occurring bacteria. The membrane, which is about 100 micrometers thick, is just below the shell and and Basab Chaudhuri and his colleagues have demonstrated that a weak acid can be used to separate it from the shell for use as a carbon dioxide adsorbent.
Currently, separating the membrane from the cuticle is not an efficient process but, with India alone consuming 1.6 million metric tons of eggs each year and global egg consumption expected to reach about 1,154 billion by 2015, the team says there is definitely an incentive for researchers to find an efficient method in order to use the membrane material in climate change amelioration. To make the process viable on an industrial scale, however, the researchers say a mechanical separation method would be needed.
Until such a method is found, Chauduri muses that we could all help reduce CO2 levels by exposing our egg membranes to the air after eating our eggs. Couldn’t hurt.