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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (04): 418-424. 上一篇    下一篇

研究论文

25 ℃时Ca5(AsxP1－xO4)3F固溶体的溶解度与稳定性研究

许立巍*,1,2，朱义年2，梁美娜2，何娜2，龙腾锐1   

  1. (1重庆大学城市建设与环境工程学院 重庆 400045)
    (2桂林理工大学环境科学与工程学院 桂林 541004)
  • 投稿日期:2010-04-10 修回日期:2010-08-22 发布日期:2010-10-18
  • 通讯作者: 许立巍 E-mail:xuliwei@glite.edu.cn
  • 基金资助:

    砷酸盐固溶体溶解度及其环境效应

Study on the Solubility and Stability of the Arsenate/phosphate Fluorapatite Solid Solution at 25 ℃

Xu Liwei*,1,2 Zhu Yinian2 Liang Meina2 He Na2 Long Tengrui1   

  1. (1School of Municipal and Environmental Engineering, Chongqing University, Chongqing, 400045)
    (2 College of Environmental Science and Engineering, Guilin University of Technology, Guangxi Guilin, 541004)
  • Received:2010-04-10 Revised:2010-08-22 Published:2010-10-18
  • Contact: Xu LiWei E-mail:xuliwei@glite.edu.cn

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通过在25 ℃和不同pH值条件下对人工合成Ca5(AsxP1－xO4)3F固溶体的溶解实验, 确定其稳定存在的pH值范围, 得出它的溶度积和生成的自由能(ΔGf0), 并讨论其用于沉淀法处理含砷废水的可行性. 结果表明, Ca5(AsxP1－xO4)3F固溶体在水中的溶解度和稳定范围与pH有关. 在酸性条件下, 水溶液中的As的浓度要比同种样品在中性和碱性条件下的浓度高10倍以上. Ca5(AsxP1－xO4)3F固溶体溶解时, As的浓度随着P∶As物质的量比升高而降低. 计算结果表明, 在25 ℃和pH＝6的条件下, Ca5(AsxP1－xO4)3F固溶体的溶度积和自由能随着P∶As摩尔比的升高而降低.

关键词: 砷, 氟磷灰石, 固溶体, 溶解度

The object of this work was to determine the solubility and stability of the synthetic Ca5(Asx- P1－xO4)3F solid solution at 25 ℃ and different pHs by batch dissolution experiments. The results indicated that the solubility and stability of Ca5(AsxP1－xO4)3F in aqueous solution were strongly dependent on the solution pH. During the dissolution, the dissolved arsenic concentration under acidic condition was ten times higher than that under neutral-alkaline condition. Based on the analytical result at 25 ℃ and pH 6, the solubility product (Ksp) and the free energy of formation (ΔGf0) for the Ca5(AsxP1－xO4)3F solid solution were calculated, which increased with the increasing mole fraction of P and As in the solid solution.

Key words: arsenic, fluorapatite, solid solution, solubility