Optimization on Synthetic Conditions of Fluoride Apatite Coated Titanium Dioxide in Simulated Body Fluid

An acid resistant fluoroapatite coated titanium dioxide (FAp-TiO2) 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, the optimization of synthetic conditions of FAp-TiO2 was investigated in terms of the amount of the fluorine (F-) added to the simulated body fluid, the reaction temperature and the time. The addition of F- to simulated body fluid was performed after coating HAp on the surface of TiO2 surface. The crystallinity of FAp phase generated on the TiO2 was strongly affected by changing the reaction conditions. The optimized synthetic conditions of FAp-TiO2 as photocatalyst were the addition of 0.25 mM-0.5 mM F- in the fluid and then the reaction time for 3 h at 60°C. The adsorptivity and the photocatalytic activity of the FAp-TiO2 in the optimum conditions were investigated using the butyric acid and trimethylamine as model solutions. Consequently, the FAp-TiO2 could obtain higher adsorptivity and photocatalytic activity for trimethylamine, rather than the uncoated TiO2.