Maximising carbonate content in sodium-carbonate Co-substituted hydroxyapatites prepared by aqueous precipitation reaction

We report the synthesis of a range sodium-carbonate co-substituted hydroxyapatite compositions with sodium and measured carbonate contents ranging from approximately 0.4–0.8 ​wt% 4.4–14.2 ​wt%, respectively, via aqueous precipitation reaction between calcium hydroxide, phosphoric acid either or hydrogen-carbonate. A subsequent heat treatment in dry CO2 at 600 ​°C allowed for Na–CO3 apatite containing 17.7 to be prepared, one largest reported date such material. Deconvolution FTIR data showed that incorporated ions were situated on both hydroxyl phosphate sites. Increasing 300 up ​°C, prior decomposition point these compositions, trend towards an increase distribution main B-site expense decrease A-site, although overall total content increased increasing temperature. Changes lattice parameter dominated, marked addition carbonate, when samples further heated CO2. These results demonstrate highly carbonated hydroxyapatites can obtained using simple, room temperature, starting reagents unlikely pose significant environmental risks, adding degree flexibility preparation materials scope their application fields beyond biomaterials.