Abstract

The hydrolytic stability of calcium and magnesium phosphates in aqueous solutions was studied in a wide pH range and in the presence of NaCl and CaCl₂ electrolytes: calcium hydrogen phosphate and tricalcium phosphate are stable at pH 4.5‒10.0, and hydroxyapatite, at pH 3.0‒12.0. An increase in the ratio of the solution volume to the weight of phosphates from 250 to 500 mL/g leads to an increase in the degree of hydrolysis by a factor of 1.4–1.9. In the presence of 0.01 M NaCl and 0.001 M CaCl₂, all samples exhibit high hydrolytic stability, and an increase in concentration to 1.0 M NaCl and 0.01 M CaCl₂ results in deprotonization of hydrophosphate ions and the transformation of magnesium phosphates to calcium phosphates.

中文翻译：

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磷酸钙和磷酸镁吸附剂在水和电解质溶液中的行为特征

摘要

研究了水溶液中磷酸钙和磷酸镁在较宽 pH 范围内和存在 NaCl 和 CaCl ₂电解质的情况下的水解稳定性：磷酸氢钙和磷酸三钙在 pH 4.5-10.0 下稳定，羟基磷灰石在 pH 3.0-1 下稳定12.0. 溶液体积与磷酸盐重量之比从 250 增加到 500 mL/g 会导致水解度增加 1.4-1.9 倍。在 0.01 M NaCl 和 0.001 M CaCl ₂存在下，所有样品都表现出高水解稳定性，并且浓度增加到 1.0 M NaCl 和 0.01 M CaCl _{2 会}导致磷酸氢根离子去质子化，并将磷酸镁转化为磷酸钙。