Work

Powders Synthesized from Calcium Chloride and Mixed-Anionic Solution Containing Orthophosphate and Carbonate Ions

Year: 2025

Type: article

Abstract: Low crystalline hydroxyapatite was synthesized from an aqueous solution of calcium chloride CaCl2 and a mixed-anionic (HPO42- и CO32-) aqueous solution prepared from potassium hydro-phosphate trihydrate K2HPO4 3Н2О and potassium carbonate K2CO3. The interaction of K2CO3 and K2HPO4 salts during synthesis from a mixed anionic solution in the reaction zone without additional regulation provided the pH level necessary for the synthesis of hydroxyapatite. For comparison, as references, powders were also synthesized from an aqueous solution of calcium chloride CaCl2 and from aqueous solutions of either potassium hydrophosphate K2HPO4 or potassium carbonate K2CO3. The phase composition of the powder synthesized from aqueous solutions of calcium chlo-ride CaCl2 and potassium hydrophosphate K2HPO4 included brushite CaНРО4·2H2O. The phase composition of the powder synthesized from aqueous solutions of calcium chloride CaCl2 and po-tassium carbonate K2CO3 included calcite CaCO3. The phase composition of all synthesized pow-ders contained potassium chloride (sylvine) KCl as a reaction by-product. After heat treatment at 1000 °C of the powder containing low crystalline hydroxyapatite and potassium chloride (sylvine) KCl, powder of chlorapatite Са10(РО4)6Cl2 was obtained. After heat treatment of a powder con-taining brushite CaНРО4·2H2O and potassium chloride (sylvine) KCl at 800 and 1000 °C, a powder with the phase composition including β-calcium pyrophosphate β-Ca2P2O7, β-calcium ortho-phosphate β-Ca3(PO4)2 and potassium-calcium pyrophosphate K2CaP2O7 was obtained. Heat treatment of calcite CaCO3 powder at 800 °C, as expected, led to the formation of calcium oxide CaO. Synthesized powders including biocompatible minerals such as hydroxyapatite, chlorapatite, brushite, monetite, calcium pyrophosphate, calcium potassium pyrophosphate, tricalcium phos-phate, calcite can be used for creation of biocompatible inorganic materials or composite materials with a biocompatible polymer matrix. The potassium chloride present in the synthesized powders can act as one of the precursors of biocompatible minerals such as chlorapatite or calcium potassium pyrophosphate; or it can be treated as a removable inorganic porogen.

Source: Compounds

DOI: 10.3390/compounds5040041