抄録
A calcium hydrogen phosphate dihydrate (DCPD) reacts with fluoride ion in a solution to form fluorapatite (FAp). This reaction is very selective and efficient enough. In previous reports, we have appeared that this reaction needs “lag time”. The lag time is induction periods to form “nano-surface structure” on surface of the DCPD particles. Control of the lag time is very important for applying this reaction to fixation of fluoride in the environment. In this paper we assessed effects of reaction temperature and fluoride ion in the aqueous solution on the lag time. Relationship between the lag time and reaction temperature was fit Arrhenius’s equation and activation energy was 84.3 kJ mol-1. We appeared that induction of nano-surface structure” on surface of the DCPD particles is inhibited by fluoride ion in the solution. A “nano-surface DCPD” having nano-surface structure on its surface was easily obtained by mixing with DCPD and water. The obtained “nano-surface DCPD” reacted with fluoride ion in the aqueous solution without the lag time and applicable to removal of fluoride in the environment.
