Nanoscale conversion of chlorapatite into hydroxyapatite using ultrasound irradiation

Abstract

Abstract:The ultrasound-assisted conversion of chlorapatite nanoparticles obtained from a natural phosphate rock into hydroxyapatite nanocrystals was achieved within one hour. The process had no significant impact on particle crystallinity but led to a significant decrease of the colloidal size. Similar variations were obtained for hydroxyapatite nanoparticles treated in the same conditions, suggesting that these variations are not due to the compositional modification. Analyses of the solubility properties of the two phases and of the ionic contents of the reaction medium suggest that the undersaturated conditions of the reaction and the cavitation phenomena favor surface exchange and erosion mechanisms over bulk amorphization.

Controlling the Product Crystal Size Distribution by Strategic Application of Ultrasonication

“…This is, as expected, much higher in comparison to the MSZWs of 8.1, 7.2, and 5.1 °C observed in the sonicated experiments performed with a cooling rate of 0.5 °C/min and ultrasound powers of 60, 103, and 144 kg/m 3 , respectively. The decrease in MZW reflects that nucleation in a supersaturated solution is stimulated by the sonication, increasingly so with increasing sonication power. , The MSZW can be altered by changing the ultrasonication power; MSZW of the sonicated crystallization performed at 0.5 °C/min is significantly lower than that of a conventional cooling crystallization even when the crystallization is performed at a higher (1 °C/min) or lower cooling rate (0.1 °C/min). As evidenced from Figure , the cooling crystallization performed under silent conditions (no ultrasound) with a very low cooling rate still produced a higher MSZW, in comparison to the CU experiments.…”

Photoluminescent Hydroxylapatite: Eu3+ Doping Effect on Biological Behaviour

“…HAp synthesis, with its diverse morphologies, structures and textures, has attracted much interest in academic and industrial research for many heterogeneous catalysis applications [7,8,9]. Numerous synthetic routes for obtaining hydroxylapatite were developed over time, and can be divided in four main categories: (1) wet methods [10,11,12], (2) dry methods [13], (3) microwave-assisted methods [14,15,16], ball-milling [17,18,19] or ultrasound methods [20,21], and (4) miscellaneous methods [22]. Depending on the reagents and conditions, each category offers several variations [23,24].…”