Food waste eggshell valorization through development of new composites: A review

The total amount of annual eggshell waste is similar as the amount of plastics waste input in the oceans every year. Hence, the management of this eggshell waste is a major challenge. The last five years have seen a dramatic increase in research dedicated to the use of eggshell waste as source materials for the development of novel sustainable composites. This paper provides a review of the broad range of eggshell waste use in polymer, metal and ceramic composites, and in other applications such as adsorbents, catalysts, additives and functional materials. The different types and sources of CaCO3 are presented. An overview is given about the eggshell treatment methods and parameters, which fall broadly in two categories, low temperature treatment of CaCO3 particles, and high temperature treatment involving carbonization or calcination. The mechanical properties of structural composites with eggshell derived particles are discussed for polymer, metal and ceramic matrix materials. A brief view on commercialization is presented, and the paper concludes with the main findings and suggestions for future research developments.