Modification and characterization of chicken eggshell for possible catalytic applications

Researchers have shown considerable interest in finding a sustainable, low cost, and readily available substitute for the commercial calcium oxide (CaO) catalyst. In this work, raw chicken eggshell was modified by boiling and calcination at 900 °C for 3 h. The x-ray diffraction characterization revealed that while the proportion of CaCO₃ in the raw and boiled samples was found to be 79.3 % and 99.2 % respectively, the CaCO₃ had been converted to 63.8 % CaO and CO₂ in the calcined sample. This was due to the thermal decomposition during calcination. The outcome of the infrared spectroscopy showed that the raw and boiled chicken eggshell presented a similar absorption profile with peaks at 1 394 cm^-1, 873 cm^-1, and 712 cm^-1, which were as a result of the presence of asymmetric stretch, out-of-plane bend, and in-plane bend vibration modes. The major peaks presented by the calcined sample at 3642 cm^-1 can be attributed to the OAH stretching vibration and bending hydroxyl groups present in Ca(OH)₂. The Brunauer-Emmett-Teller surface areas for the raw, boiled and calcined chicken eggshell were found to be 2.33 m²/g, 3.26 m²/g, and 4.6 m²/g respectively, indicating increased catalytic activity of the calcined sample. Overall, boiling was found to have a negligible effect on the chicken eggshell, while high-temperature calcination greatly affected the pore size, surface area, composition, and thermal decomposition profile of the chicken eggshell sample.