Synthetic alkaline-earth hydroxyapatites: Influence of their structural, textural, and morphological properties over Co2+ ion adsorption capacity

This work addresses the synthesis of nanocrystalline barium, strontium, and calcium hydroxyapatites (Ca-HAps) via the chemical precipitation method, followed by calcination. To give a coherent picture of the most important structural, textural, and morphological properties of these materials and to investigate the influence of these characteristics over Co2+ ion adsorption capacity from aqueous solutions, the powders prepared were systematically characterized by X-ray diffraction, N-2-physisorption measurements, scanning electron microscopy (SEM), energy dispersive X-ray spectrometry, and Fourier Transformed Infrared spectroscopy (FTIR). The results clearly showed that the Ca-HAp obtained exhibits better nanocrystallinity, greater structural stability, high surface area, high total pore volume, and mesoporosity, compared with the other synthesized hydroxyapatites, and that these physicochemical properties share a direct correlation with favorable Co2+ ion adsorption capacity at room temperature and pressure. The results proved that the physicochemical features of resulting alkaline-earth hydroxyapatites, prepared via the chemical precipitation method, played a fundamental role during the adsorption of heavy metal (with high toxicity) from aqueous solutions.

Automated summary

This study synthesized nanocrystalline barium, strontium, and calcium hydroxyapatites, showing better nanocrystallinity, structural stability, and adsorption capacity. The physicochemical properties of these materials were directly correlated with their adsorption capacity for Co2+ ions.