Synthesis of Carbonated Hydroxyapatite Derived from Snail Shells (Pilla ampulacea): Effect of Carbonate Precursor to the Crystallographic Properties

This study aimed to investigate the effect of the amount of carbonate in synthesis to the crystallography properties of carbonated-hydroxyapatite (CHAp) using the snail shells as the calcium source. Snail shells were cleaned, milled, and sintered at 1000°C for 4 hours to get CaO powder. CHAp synthesized by co-precipitation method. The molar ratio CO<inf>3</inf> ^2-/PO<inf>4</inf> ^3- was varied 0/6, 2/6, 3/6, and 6/6. Meanwhile, the molar ratio of Ca/P was kept at 1.67. After synthesis, the solution was aged, centrifugally washed, dried, and sintered at 400°C for 2 h in the air atmosphere. A scanning electron microscope (SEM) was used to observe the morphology of CHAp. An energy dispersive spectroscopy (EDS) was used to determine the chemical composition of CHAp. An X-Ray Diffractometer (XRD) was conducted to analyze the crystallography of CHAp. Fourier transform infrared (FT-IR) was used to evaluate the chemical structure of the CHAp. The XRD spectra of CHAp of all variations show they have apatite phase. There is no secondary phase observed in XRD spectra. The results of FTIR and EDS supported the XRD results. The increasing of carbonate amount in synthesis decreased the crystallinity and crystallite size of CHAp. The lattice parameter a-axis was decreased, but the lattice parameter c-axis was increased as the amount of carbonate increased in the synthesis process. The increasing of carbonate amount in synthesis decreases the crystallite size of CHAp. The results demonstrate that the amount of carbonate in synthesis affects the crystallography properties of CHAp.