Abstract
Octacalcium phosphate (OCP) precipitates on diopside in simulated body fluid. We investigated to remove the
phosphate in solution containing phosphate by using this precipitation reaction. By immersing diopside sintered
at different temperatures in a 100 μmol/L phosphate solution, it was found that the diopside sintered at 650ºC
yielded a removal rate of 91.1% and removed a large amount of phosphate. Surface observation of diopside after
the removal of phosphate confirmed the presence of precipitates on the surface. Further, X-ray diffraction
analysis of diopside immersed in a 10 mmol/L phosphate solution showed a peak near 32°, which was considered
to originate from OCP. This is presumed to be due to the superior OCP precipitation ability by adsorption by
surface hydroxyl groups and consumption of phosphate. From the results of this study, it is expected that the
synthesized diopside is excellent for phosphate removal and is thus useful as a phosphate-removing material.
