Synthesis of nano-hydroxyapatite (nHA) from waste mussel shells using a rapid microwave method

Nano-crystalline hydroxyapatite (HA, Ca-10(PO4)(6)(OH)(2)) was produced from waste mussel shells using a rapid microwave irradiation method. Mussel shells were converted to rod like nano-crystalline HA particles of 30-70 nm long using 0.1 M EDTA as a chelating agent for 30 min after an appropriate pretreatment and an irradiation step in a microwave with a power of 1.1 kW. The produced HA was characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma mass spectrometry (ICP-MS) to determine the morphology, particle size, crystal phases, elemental composition and thermal behaviour. Furthermore, to benchmark the synthesized HA obtained from mussel shells, it was compared with a commercially pure HA (Sigma Aldrich). The thermal analysis showed that the synthesized HA has remarkable heat stability at 1000 degrees C, and the XRD and FTIR results showed a high purity of the synthesized HA powders. Compared to the conventional hydrothermal treatment, microwave-assisted method has the advantages of an increased rate of HA formation. The obtained HA have potential engineering applications as materials for bone-tissues. (C) 2014 Elsevier B.V. All rights reserved.