Effect of H3PO4 reactant and NaF additive on the crystallization and properties of brushite

¹Department of Bioelectronics & Biosensors, Alagappa University, Karaikudi 630003, TN, India

²Department of Physics, Sri Sarada College for Women, Salem  636016, TN, India

³Department of Physics, Periyar University, Salem 636 011, TN, India

Adv. Mater. Lett., 2011, 2 (3), pp 227-232

DOI: 10.5185/amlett.2011.1217

Publication Date (Web): Apr 08, 2012

Copyright © IAAM-VBRI Press

E-mail: sekar2025@gmail.com

Abstract

Calcium hydrogen phosphate dihydrate (CaHPO₄.2H₂O, CHPD) or brushite crystal is a well known urinary substance found frequently in urinary stones. The CHPD crystals have been crystallized in sodium metasilicate gel (SMS) at room temperature under pH 6 in the presence of sodium fluoride. Here, H₃PO₄ and CaCl₂ were used as reactants which resulted in simultaneous crystallization of mostly dentritic brushite crystals and a small quantity of hydroxyapatite (HA). On the other hand, use of Na₂HPO₄ and CaCl₂ as reactants yielded the large quantity of HA along with platelet brushite crystals. In both the cases, addition of sodium fluoride is found to inhibit the nucleation and subsequent growth of brushite crystals. The crystal morphology, structure and elemental composition of the grown crystals have been analyzed using SEM-EDX and powder XRD studies. Functional groups present in the grown crystals have been confirmed from the vibrational frequencies of the recorded FTIR spectrum.

Keywords

Brushite, gel growth, sodium fluoride, X-ray diffraction, FTIR