Thermal stability of nano hydroxyapatite synthesized from sea shells through wet chemical synthesis

Nano hydroxyapatite (HA) was synthesized by a wet chemical reaction route using powdered sea shells (CaO) as starting material which was converted to calcium hydroxide (Ca(OH)2) and subsequently reacted with phosphoric acid (H3PO4) by slow addition, maintaining a Ca:P ratio of 1.67. The synthesized samples showed X-ray diffraction (XRD) patterns corresponding to phase pure hydoxyapatite. The prepared HA powder was subjected to furnace and microwave heating to compare the decomposition of HA and study the crystallite sizes. The morphology of the as synthesized nano HA was rod shaped and the crystallite size was about 101 nm. Microwave heated HA showed no decomposition and yielded crystallite sizes of lesser dimensions than furnace heated HA at various heating temperatures.

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► Nano hydroxyapatite (HA) was synthesized by a wet chemical reaction route rather than the usual hydrothermal method, using powdered sea shells (CaO) as starting material.
► Morphology of the as synthesized nano HA was rod shaped with the absence of secondary phases and the crystallite size was about 101 nm.
► Prepared HA powder was subjected to furnace and microwave heating to study the thermal stability and variation in crystallite sizes of HA.
► Microwave heated HA showed no decomposition to other secondary phases and yielded crystallite sizes of lesser dimensions than furnace heated HA at various heating temperatures.
► This study confirms the suitability of HA prepared from sea shells which is most suitable for in-vivo conditions than the other secondary phases.