Electrolytic One-Pot Synthesis of Group II Nanohydroxyapatite

SUPPORTING INFORMATION

Electrolytic one-pot synthesis of Group II nanohydroxyapatite

S1. Preparation of solutions

1. Ca-EDTA-PO43- solution:

20 g of NaOH was dissolved in 550 mL DDW, and then 93.05 g of EDTA disodium salt was added. The mixture was stirred and heated gently until obtain a translucent solution. To this solution was added 36.75 g of CaCl2·2H2O dissolved in 100 mL of DDW and the pH adjusted to 7.5. Finally 23.83 g from K2HPO4 dissolved in 100 mL was added. The pH of the solution is adjusted with NaOH (1 + 1) to the working pH and volume adjusted to 1 L in a volumetric flask.

1. Ca/Mg-EDTA-PO43- (Ca:Mg 4:1) solution:

10.96 g of EDTA acid was added to 50 mL DDW, then 5 mL NH3 (ac.) solution was added. The mixture was stirred and heated gently until obtain a translucent solution. To this solution was added 4.4 g of CaCl2·2H2O and 1.5 g of MgCl2·H2O dissolved in 50 mL of DDW, and the pH adjusted to 7.5 with NH3 (ac.). Finally 3.95 g from K2HPO4 dissolved in 30 mL was added. The pH of the solution is adjusted with NH3 (ac.) to pH 7.0 and volume adjusted to 150 mL in a volumetric flask.

1. Ca/Mg-EDTA-PO43- (Ca:Mg 6:1) solution:

10.96 g of EDTA acid was added to 50 mL DDW, then 5 mL NH3 (ac.) solution was added. The mixture was stirred and heated gently until obtain a translucent solution. To this solution was added 5.1 g of CaCl2·2H2O and 0.51 g MgCl2·H2O dissolved in 50 ml of DDW, and the pH adjusted to 7.5 with NH3 (ac.). Finally 3.95 g from K2HPO4 dissolved in 30 mL was added. The pH of the solution is adjusted with NH3 (ac.) to pH 7.0 and volume adjusted to 150 mL in a volumetric flask.

1. Sr-EDTA-PO43- solution:

10.96 g of EDTA acid was added to 50 mL DDW, then 5 mL NH3 (ac.) solution was added. The mixture was stirred and heated gently until obtain a translucent solution. To this solution was added 7.94 g of Sr(NO3)2 dissolved in 40 ml of DDW and the pH adjusted to 7.5 with NH3 (ac.). Finally 3.95 g from K2HPO4 dissolved in 30 mL was added. The pH of the solution is adjusted with NH3 (ac.) to 7.0 pH and volume adjusted to 150 mL in a volumetric flask.

1. Ba-EDTA-PO43- solution:

10.96 g of EDTA acid was added to 50 mL distilled water, then 10 mL NH3 (ac.) solution was added. The mixture was stirred and heated gently until obtain a translucent solution. To this solution was added 9.16 g of BaCl2·2H2O dissolved in 50 ml of distilled water and the pH adjusted to 11.0 with NH3 (ac.). Finally 3.95 g from K2HPO4 dissolved in 30 mL was added. The pH of the solution is adjusted with NH3 (ac.) to pH 11.0 and volume adjusted to 250 mL in a volumetric flask.

S2. Electrolytic synthesis conditions.

The parameters studied are divided in two major groups: P-series (pH) and D-series (current density). It also shows the conditions for the synthesis of Sr-HA, Ba-HA, Mg-Ca-HA samples and yield in gram hours-1 (g h-1).

S3.Calculated a and b cell parameters.

S4. EDS analysis of some Ca-HA samples.

S5. XRD patterns for Ca-HA synthesized associated with pH variable (P01-P14). Arrows denotes change in resolution and peak broadening in the region of 2Ɵ=31-34º. It shows the relative intensity change corresponding to the crystallographic plane (002) and (004) signaled with lower pH solution.

S6. EDS analysis of the Ca-Mg-HA1 sample.