天然多孔材料水热合成羟基磷灰石

Hydroxyapatite transformed hydrothermally from natural porous material

研究发现牡蛎白垩层是一种天然方解石质多孔微结构材料,并以其为原料,采用水热法在90℃水浴、常压条件下与磷酸氢二铵溶液反应生成羟基磷灰石。产物通过傅立叶红外光谱(FTIR)、X射线粉末衍射(XRD)、扫描电子显微镜(SEM)进行分析。结果表明,常压下反应15min就出现了羟基磷灰石。48h后白垩层几乎完全转化为羟基磷灰石,并且生成的羟基磷灰石仍完好的保留原多孔微结构。这种转化是通过两种历程完成的,即方解石表面的溶解-重结晶及其内部的固态局域规整离子交换反应。

The chalky layer from the oyster shell studied, was found to be a natural micro-porous structure material calcite, with which the hydroxyapatite was synthesized in the phosphatic solution at 90℃ water hath heating and atmospheric press. X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, and scanning electron microscopy （SEM） were employed to characterize the products prepared by chalky layer. The resuits show that the hydroxyapatite would be formed as long as the reactants underwent only 15rain hydrotherreal reaction at atmospheric press. After 48h reaction, the chalky layer almost converted entirely to hydroxyapatite and the hydroxyapatite still retained the original integrity of the micro-porous structure. This conversion included two reaction processes. The exterior calcite converted to hydroxyapatite via dissolution-reerystallization; meanwhile the interior calcite-conversion referred to a solid-state topotactic ion exchange reaction.