Публікація: Synthesis of Pure Hydroxyapatite by Ion Exchange Reaction.
Завантаження...
Дата
2019
Автори
Назва журналу
ISSN журналу
Назва тома
Видавництво
Анотація
An ion-exchange reaction for the synthesis of hydroxyapatite (HAP) in a constant alkaline medium
using preliminary dry homogenization is proposed in this work. Sodium hydrogen phosphate Na2HPO4,
calcium chloride CaCl2 and calcium hydroxide Ca(OH)2 were chosen as precursors. When Na2HPO4
interacts with calcium salts in an alkaline medium, Na+ ions are replaced by Ca2+ ions. The CaCl2 salt was
chosen as the source of Ca2+ ions, since in this case one of the reaction products is sodium chloride, which is
subsequently easily washed out. The required pH of the medium was achieved by adding calcium
hydroxide to the starting materials, which was also a source of Ca2+ ions. Heating in a water bath provided
a constant influx of water molecules, which is necessary for the dissociation of the molecules of the
substances involved in the reaction. In dry synthesis, it is rather difficult to obtain stoichiometric HAP due
to the uneven distribution of ions in the reacting mixture. The chemical reaction in a humid environment
can reduce the influence of this factor. It was assumed that since, in addition to HAP, the reaction products
are water-soluble compounds, a slight change in the ratio of the starting components can be used to control
the stoichiometry of HAP, as well as the ratio of the final reaction products. Additional products formed
during the reaction were removed by washing the resulting powder with distilled water. The washed and
dried HAP powder was annealed in an oven at T 700 °C. Studies carried out by methods of X-ray phase
analysis, scanning electron and transmission microscopy showed that the material obtained is a singlephase
hydroxyapatite powder with a Ca/P ratio close to 1.67. It was found that the particles of HAP powder
obtained as a result of synthesis with subsequent washing have the shape of needles with a thickness of 10
to 40 nm and a length of 30 to 200 nm. Annealing of the powder at a temperature of 700 °C leads to
agglomeration of particles, as well as to rounding of their shape.
Опис
Ключові слова
Nanocrystalline hydroxyapatite, Phase and elemental composition, X-ray phase analysis
Бібліографічний опис
O.V. Glukhov / M.B. Ivanov, E.V. Krytsyna, T.N. Vershinina, D.A. Kolesnikov, E.A. Kudryavtsev, N.A. Dubrovina, N.A. Volkovnyak, O.V. Gluchov.Synthesis of Pure Hydroxyapatite by Ion Exchange Reaction. // Journal of Nano- and Electronic Physics. - Vol. 11. - No 6. - p.06031(4pp).