Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Textural characteristics of synthesized alkaline-earth hydroxyapatite materials and Co2+ ion adsorption capacities in percentage_
| Sample | SBET (m2 g−1)a | Vt (cm3 g−1)b | dp (nm)c | Co2+ ion adsorption capacity (%) |
|---|---|---|---|---|
| Ba-HAp | 0.5216 | 0.0011 | 8.9231 | 6.03 ± 0.39 |
| Sr-HAp | 1.3874 | 0.0057 | 16.5310 | 17.46 ± 0.79 |
| Ca-HAp | 59.7000 | 0.1120 | 7.5046 | 56.84 ± 1.08 |