**5. Conclusion**

There are large tonnes of eggshells and seashells discarded in landfill annually from poultry and food industries. Most of the seashells and eggshells are piled up on the seashore and thus would cause risks to water resources and public health. The applications of these biomaterials in construction such as concrete and cement production, catalyst manufacture, adsorbent for wastewater treatment, source of calcium in animal feed, manufacture of hydroxyapatite biomaterial, and additive in plastic manufacture has been explored extensively in the literature. These biomaterials contain about 96% calcium carbonate mineralogical component from which calcium oxide can be produced through thermal treatment. The carbonation – calcination loop of CaO/CaCO3 process has been investigated for CO2 capture potentials. Herein, the application of eggshell and seashell derived-CaO sorbent in the capture of carbon dioxide from flue gas is reviewed. The utilisation of this waste shell offers economic as well as environmental benefits because they are abundant, renewable and cheap. The CaO sorbent derived from eggshell and seashell has demonstrated the potential for carbon dioxide capture. It was also found that pre-treatment and regeneration provide means of restoring reactivity and CO2 capture capacity over multicyclic usage. Although this ensured sustainability and sorbent recyclability, the performance decreases ten cycles after regeneration. The future outlook will be to improve the carbon dioxide capture capacity and thermal stability of these biomaterials over multicycles operations.
