The Effect of pH on the Characteristics of Carbonate Hydroxyapatite Based on Pearl Shell (Pinctada maxima)

Abstract

Carbonate Hydroxyapatite (CHAp) is one of biomaterial that can be synthesized from natural ingredients. CHAp has been successfully synthesized from pearl shells (Pinctada maxima) using the precipitation method. The pH of the synthesis process affects several characteristics of CHAp, including crystallinity, crystal size, morphology, and carbonate content. XRD data showed that CaO obtained from pearl shell powder through the calcination process. The highest crystallinity of CHAp occurs when the pH is 8, and the lowest is at pH 10. The size of the crystalline CHAp decreased when the pH increased. Based on SEM data, the morphology of CaO looks more tenuous than the morphology of CaCO3 due to CO2 release during the decomposition process. The magnitude of pH greatly influences the morphology of CHAp where morphology looks different for different pH. EDX data shows that CHAp has the highest carbonate content when pH 10 with a smaller Ca/P ratio when the carbonate content gets bigger.