Abstracts Book - IMRC 2018

• SF5-O031 Invited Talk
IMPROVEMENT OF REACTIVITY OF DICALCIUM PHOSPHATE
DIHYDRATE (DCPD) FOR REMOVAL FLUORIDE ION IN THE WATER
ENVIRONMENTS (INVIED)
Masamoto Tafu 1 , Saori Takamatsu 1 , Takeshi Toshima 2
1 National Institute of Technology, Toyama College, Department of Applied Chemistry and
Chemical Engineering, Japan. 2 National Institute of Technology, Toyama College, Department of
Mechanical Engineering, Japan.
Fluoride in the water environments is one of the important environmental
issues because of its health impact such as dental fluorosis. To removal fluoride
ion in the water environments, bone char (bio-apatite) is good candidate.
However, adsorption capacity of bone char in low fluoride level decrease to a
few mg/kg[1]. We have investigated application of transform reaction of
dicalcium phosphate dihydrate (DCPD, CaHPO 4 . 2H 2 O) with fluoride ion to
removal fluoride in the water environments [2]. DCPD reacts with fluoride and
form stable fluorapatite (FAp, Ca 10 (PO 4 ) 6 F 2 ). We appared that removal amount
of DCPD for fluoride ion was around 10 mg/g in lower fluoride revel that is five
times of conventional bone char [3]. DCPD/carbon hybrid was easily obtained
bone char by acid treatment of the bone char. Reaction between DCPD and
fluoride ion release phosphate ions. Addition of multiple calcium salts into DCPD
was effective to inhibit phosphate release. In this presentation, recently
achievement of our studies about production, characterization and applications
of DCPD and its hybrid for removal fluoride ion in the water environments.
Reference: [1] A. Medellin-Castillo et al., Ind. Eng. Chem. Res., 46, 9205-9212
(2007), [2] M. Tafu and T. Chohji, J. Ceram. Soc. Jpn., 113, 263-267 (2005), [3] M.
Tafu et al., Euro-Mediter. J. Environ. Integr., 1: 4 (2016)
Keywords: Fluoride, Calcium phosphate, Water environments
Presenting authors email: tafu@nc-toyama.ac.jp