Materials from Eggshells and Animal Bones and Their Catalytic Applications

The use of exhaustible natural resources to make materials for catalytic applications with limited service life, which in due course end up as waste, is an economic sabotage. There exist a number of developed techniques to recover value-added materials from waste eggshells and animal bones. The objective of this chapter is to shed light on techniques for recovering valuable materials from these wastes and highlight potential applications with special attention on heterogeneous catalysis. In this chapter, an inclusive review is presented at several scales, where eggshell and animal bones are used as raw materials to produce valuable materials such as calcium carbonate/oxide, calcium phosphate, adsorbent, filler, and hydroxyapatite (HA). Their catalytic applications in biodiesel production, gasification, carbon dioxide capture, organic synthesis, fuel cell membrane, hydrogen production via water-gas shift (WGS) reaction, methane oxidation coupling, and other prospective reactions were explored. Eggshells and animal bones are proven source of renewable and greener catalyst to substitute conventional counterparts. They have also demonstrated suitability and stability for industrial applications including adsorbent for wastewater treatment and flue gas treatment sorbent, particularly carbon dioxide capture. Additionally, the present chapter highlights potential areas that need scale-up to permit the use of these materials as biofilter adsorbent and heterogeneous catalysts. It also identifies areas at research and development stages. This chapter discusses the properties of eggshells and animal bones that make them potential candidate for sorbent, HA material manufacture for medical applications and in heterogeneous catalysis. Finally, the various applications of eggshell and animal bones as catalyst are presented and discussed. This promotes the concept of circular economy in which waste materials are reused as a raw material for the production of new materials or recycled into more useful material.