25℃时Ca_5(As_xP_(1-x)O_4)_3F固溶体的溶解度与稳定性研究  

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

作　　者：许立巍[1,2] 朱义年[2] 梁美娜[2] 何娜[2] 龙腾锐[1] 

机构地区：[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

出　　处：《化学学报》2011年第4期418-424,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.40773059)资助项目

摘　　要：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(?Gf0),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.The object of this work was to determine the solubility and stability of the synthetic Ca5（AsxP1-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 （Ksv） and the free energy of formation （△Gf^0） 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.

关 键 词：砷 氟磷灰石 固溶体 溶解度 

分 类 号：O645.12[理学—物理化学]