Effects of amino acids on conversion of calcium carbonate to hydroxyapatite

摘要: Conversion of calcium carbonate (calcite; CC) to hydroxyapatite (HAp) was examined when the CC particles sub μm size were soaked at 37 °C for up 10 d in 0.15 M K2HPO4 (20 ml), whose pH set 3–12. Here, solution contained amino acids, such as glutamine (Glu), arginine (Arg), and glycine (Gly), their content varied from 0–1.0 g per ml solution. From X-ray diffraction (XRD) intensity 104 211 diffractions calcite apatite, respectively, it seen that presence acids promoted conversion. This supported by thermogravimetry (TG) results. The highest promotion observed 0.5 addition phosphate solution, while Glu showed among Gly lowest. A scanning electron microscopy study indicated petal-like HAp nano-crystallites covered entire surface they with 0.1 or more acid d. XRD ratio 104(CC)/211(HAp) greater conversion solutions 3 6 than alkaline solutions. attributed dissolution acidic solutions, which confirmed bubbling these