The stabilities of calcium arsenates at 23+/-1 degrees C.
The stabilities of calcium arsenates at 23+/-1 degrees C.
复制标题
砷酸钙在 23 /-1 °C 下的稳定性。
DOI：
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发表时间：
1999
影响因子：
13.6
通讯作者：
Brown
中科院分区：
文献类型：
--
作者：
Bothe;Brown
砷酸钙化合物的稳定性，建立了由不同的摩尔Ca/As比的悬浮液的分析。溶液化学分析确定了钙和砷的浓度以及pH值。显示出形成的相按pH值下降的顺序为Ca（4）（OH）（2）（阿索（4））（2）·4 H（2）O、Ca（5）（阿索（4））（3）OH（砷酸盐-磷灰石）、Ca（3）（阿索（4））（2）.323H（2）O、Ca（3）（阿索（4））（2）.414H（2）O、Ca（5）H（2）（阿索（4））（4）.9H（2）O -铁铝榴石、Ca（5）H（2）（阿索（4））（4）.9H（2）O -纤锌矿和CaHAsO（4）.H（2）O。钙和砷的分析浓度和pH值用于估计溶度积。然后通过使用计算机程序PhreeqC将分析数据与计算的K（sp）值进行比较，对估计值进行细化。由精制的溶解度积，砷酸钙水合物形成的自由能计算如下：Ca（4）（OH）（2）（阿索（4））（2）.4H（2）O（-4941 kJ/mol），Ca（5）（阿索（4））（3）OH（-5087 kJ/mol），Ca（3）（阿索（4））（2）.3 23H（2）O（-3945 kJ/mol），Ca（3）（阿索（4））（2）.4 14H（2）O（~ 4085 kJ/mol）、Ca（5）H（2）（阿索（4））（4）.9H（2）O -铁钒酸盐（~ 7808 kJ/mol）、Ca（5）H（2）（阿索（4））（4）.9H（2）O -钙钛矿（~ 7803 kJ/mol）和CaHAsO（4）.H（2）O（~ 1533 kJ/mol）。与其他关于砷酸盐固定的溶解度研究不同，本研究首次考虑了可以形成的砷酸钙水合物的完整阵列，并使用缔合离子CaAsO（4）（-）、CaHAsO（4）（0）和CaH（2）阿索（4）（+）来确定其溶度积。
The stabilities of calcium arsenate compounds were established by analysis of suspensions made with varying molar Ca/As ratios. Solution chemistry analyses determined the concentrations of calcium and arsenic and pH. The phases that were shown to form in order of descending pH were Ca(4)(OH)(2)(AsO(4))(2).4H(2)O, Ca(5)(AsO(4))(3)OH (arsenate-apatite), Ca(3)(AsO(4))(2).3 23H(2)O, Ca(3)(AsO(4))(2).4 14H(2)O, Ca(5)H(2)(AsO(4))(4).9H(2)O - ferrarisite, Ca(5)H(2)(AsO(4))(4).9H(2)O - guerinite and CaHAsO(4).H(2)O. The analytical concentrations of calcium and arsenic and pH were used in estimating solubility products. The estimated values were then refined through the comparison of the analytical data with calculated K(sp) values using the computer program PhreeqC. From the refined solubility products, the free energies of formation of the calcium arsenate hydrates were calculated as follows: Ca(4)(OH)(2)(AsO(4))(2).4H(2)O (-4941 kJ/mol), Ca(5)(AsO(4))(3)OH (-5087 kJ/mol), Ca(3)(AsO(4))(2).3 23H(2)O (-3945 kJ/mol), Ca(3)(AsO(4))(2).4 14H(2)O (-4085 kJ/mol), Ca(5)H(2)(AsO(4))(4).9H(2)O - ferrarisite (-7808 kJ/mol), Ca(5)H(2)(AsO(4))(4).9H(2)O - guerinite (-7803 kJ/mol), and CaHAsO(4).H(2)O (-1533 kJ/mol). Unlike other solubility studies on arsenate immobilization, this study was the first to consider the complete array of calcium arsenate hydrates that can form and to use the associated ions, CaAsO(4)(-), CaHAsO(4)(0) and CaH(2)AsO(4)(+) in determining their solubility products.