[Optimizing the synthesis of hydroxyapatite as a method for the defluoridation of drinking water]

As the cheaper raw materials for the synthesis of hydroxyapatite as a defluoridator, calcium hydroxide and phosphoric acid are used. Hydroxyapatite is made by a hydro-synthesis method, and optimum conditions are determined by batch test for defluoridation with respect to the consumption of phosphoric acid, reaction time and acid-washed product. The results showed that the defluoridation capacity of the synthetic hydroxyapatite for break through (F- 1.0 mg/L is considered as the break through point) was F- 5.6 mg/g in column test, and F- 10.7 mg/g for saturation in column test. After optimization of the synthesis method, the defluoridation capacity of hydroxyapatite is much higher than activated alumina and bone charcoal, which are used currently.