Chemical composition of edible Oyster and Thales shells by X-ray fluorescence spectroscopy

Abstract

Oysters and Thales shells collected from the coastal areas of Nigeria were analyzed for their chemical compositions using X-ray fluorescence Spectrophotometer. The results of the elemental analyses of Oyster shell showed Ca: 47.34 ± 8.23%; Si: 23.17 ± 1.87%; Fe: 14. 83 ± 2.44% and Al: 14.65 ± 1.59%. The results of the oxides are CaO: 61.55; SiO2: 49.57; Fe2O3: 21.20; Fe3O4: 20.50; FeO: 19.08; Al2O3: 27.68. Thales showed the following elemental composition Ca: 37.23 ± 8.13; Si: 23.46 ± 8.13; Fe:14.61 ± 2.09 and Al 24.70 ± 1.65. The results of Thales oxides are CaO: 48.41; SiO2: 50.19; Fe2O3: 20.89; Fe3O4 : 20.19; FeO : 18.80; Al2O3: 46.67. The ranking of the elements are Ca>Si>Fe>Al, while the ranking order in Thales is Ca>Al >Si>Fe. The Oyster sell is composed of 95% Ca (CaCO3) and some other minerals in different percentages. The percentage of Ca (CaCO3) in Thales is about 90%. Because of the high content of CaO and CaCO3 in Oyster and Thales shells, they can be used to synthesise Hydroxyapatite (Ca10(PO4)6(OH)2. They are potential raw materials with huge ecological, agricultural and engineering benefits.