Figure 3. Energy-dispersive X-ray spectroscopy (EDX) spectra of hydroxyapatite (HAp) ( a ), 7ZnHAp Figure 3. Energy-dispersive X-ray spectroscopy (EDX) spectra of hydroxyapatite (HAp) ( a ), 7ZnHAp ( b ), and 20ZnHAp ( c ) samples. ZnHAp: zinc-doped hydroxyapatite. ( b ), and 20ZnHAp ( c ) samples. ZnHAp: zinc-doped