Synthesis and characterization of fluoride apatite in a simulated body fluid

Abstract

An acid resistant fluoroapatite (FAp) coated titanium dioxide (TiO 2) was synthesized by adding a fluoride ion (F-) to hydroxyapatite (HAp), in order to avoid dissolution of the HAp at an acidic atmosphere. In this study, different methods of adding F- to the apatite in a simulated body fluid were tested; one was synthesized by coating a simulated body fluid including Ca2+, PO43- and F- to the TiO2 (method 1), and another method was by mixing the F- after coating a simulated body fluid without the F - to the TiO2 (method 2). The apatite crystalline phase of the coated TiO2 was found to increase with F-, by using a XRD and a FT-IR. The size of crystalline apatite was strongly affected by the method of adding F-. The size of the crystalline synthesized by method 1 was larger than that by method 2. The photocatalytic activities of the apatite coated photocatalysts to organic substrates such as propionic acid were evaluated using an ion chromatography. The deterioration of FAp coating during photooxidation of the propionic acid with an UV-irradiation was largely suppressed compared with that of the HAP coating.