Carbonated hydroxyapatite starting from calcite and different orthophosphates under moderate hydrothermal conditions: Synthesis and surface reactivity in simulated body fluid

Abstract

The one-step synthesis of carbonated hydroxyapatite (CAP) using calcite and different orthophosphates was investigated in a closed batch reactor. Only orthophosphoric acid could lead to the complete decomposition of calcite particles, when the reaction temperature was set at 80 C. On the other hand, the reaction time and the dilution of the initial calcite suspension had no significant influence on the formation of the solid products. CAP was formed as the main crystalline calcium phosphate with the carbonate content in the range of 4.2-4.6 wt.%. The thermal decarbonation of the synthesized CAP started at 750 C but it was only significant at 1000 C under air atmosphere. This thermal decarbonation was total at 1200 C or above. All CAP samples and products following thermal treatments were found bioactive in the test using simulated body fluid (SBF) solution.

Hydroxyapatite-based sorbents: elaboration, characterization and application for the removal of catechol from the aqueous phase

“…These correspond to the decomposition of the residual calcium carbonate (close to 600°C) and CAP (close to 800°C). The decarbonation of CAP has been previously discussed [22,25,26]. Figure 3 shows FTIR spectra of the initial sorbents.…”

Metal-doped apatitic calcium phosphates: preparation, characterization, and reactivity in the removal of hydrogen sulfide from gas phase

“…Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 , called thereafter CaP) can be easily synthesized from a calcium source and a phosphate source such as calcium hydroxide and phosphoric acid. [22] But it can also be obtained from solid wastes such as egg shells, animal bones [23][24][25] allowing the access to low-cost materials. It has the advantage of being thermally stable and being adapted for the deposition of well-dispersed metal particles by different methods, including the conventional incipient wetness impregnation (IWI), and also the ionic exchange (CEX) thanks to its high affinity for metal cations such as Zn, Pb, Fe.…”