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

Granados-Correa Francisco, Bonifacio-Martínez Juan

Materials Science Poland

2021

Vol. 39, No. 2

252--264

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, N2-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.

Influence of Gelation Temperature on the Properties of Sol-Gel-Derived Calcium Hydroxyapatite Ceramics

Bogdanoviciene I., Tonsuaadu K., Kareiva A.

Polish Journal of Chemistry

2009

Vol. 83, nr 1

47-55

An aqueous sol-gel chemistry synthesis route has been developed to prepare calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHA) samples at different gelation temperatures. In the sol-gel processes, an aqueous solution of tartaric acid as complexing agent was used. The phase transformations, composition and micro-structural properties of the polycrystalline samples were studied by thermogravimetric analysis (TG), differential thermal analysis (DTA), energy-dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction analysis (XRD) and scanning electron microscopy (SEM). It was clearly demonstrated that temperature of initial stage of the preparation of CHA is a crucial parameter to obtain monophasic calcium hydroxy apatite powders with desired morphological properties.