The food industry generates a lot of waste products, but one of these, eggshells, could help combat climate change, according to research published in the International Journal of Global Warming this month. Basab Chaudhuri of the University of Calcutta and colleagues have demonstrated that the membrane that lines an eggshell can absorb almost seven times its own weight of the greenhouse gas carbon dioxide from the atmosphere. The carbon dioxide thus trapped could be stored in this form until energy-effective methods of using the gas could be found that would not compound the environmental problems associated with carbon emissions. Carbon dioxide is widely used in the chemical industry for the preparation of a wide range of products as well as in some settings as an alternative to toxic solvents. It might also one day be possible to efficiently convert trapped carbon dioxide into a clean fuel.
The Calcutta team explains that eggshell comprises three layers, a cuticle on the outer surface, a spongy calcium-containing middle layer and inner layer. The second and third layers are composed of protein fibers bonded to calcium carbonate. The membrane is just below the shell and is about 100 micrometers thick. Separating the membrane from the cuticle is currently not an efficient process. But, given that India alone consumes 1.6 million tonnes of eggs each year, there is certainly an incentive for improving on this situation in order to use the membrane material in climate change amelioration.