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Solubility of phosphate in the system hydroxyapatite‐clay as affected by exchangeable cations and some salts
Author(s) -
Tobia S. K.,
Milad N. E.
Publication year - 1964
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740150307
Subject(s) - solubility , chemistry , phosphate , sodium , inorganic chemistry , calcium , calcium nitrate , base (topology) , calcium carbonate , carbonate , sodium nitrate , aqueous solution , chloride , nuclear chemistry , mineralogy , organic chemistry , mathematical analysis , mathematics
Equilibrium mixtures containing water, synthetic hydroxyapatite and phosphate‐free saturated single‐base clays were prepared to determine the solubility of phosphate in absence and in presence of some sodium and calcium salts. The solubility is affected by the nature of exchangeable cations and increases in the series Ca < Mg < K < Na. The presence of sodium chloride, nitrate or sulphate increases the solubility with Ca‐ or Mg‐clays, but decreases it slightly with K‐ or Na‐clays. The corresponding calcium salts have a slight effect with Ca‐ or Mg‐clays, but decrease the solubility considerably with the K‐ or Na‐clays. Sodium carbonate decreases the solubility in all cases and calcium carbonate gives the lowest solubility. An explanation is proposed to account for the variation in phosphate concentration in the different systems.