Kinetics of hydroxyapatite precipitation at pH 10 to 11
Kinetics of hydroxyapatite precipitation at pH 10 to 11
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DOI：
10.1016/s0142-9612(00)00166-6
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发表时间：
2001-02-01
期刊：
影响因子：
14
通讯作者：
Cui, JH
中科院分区：
文献类型：
--
作者：
Liu, CS;Huang, Y;Cui, JH
本文研究了在pH 10-11、钙离子浓度大于0.5mol/l条件下，羟基磷灰石（HAP）从水溶液中沉淀的机理和动力学。结果表明，反应经历了由磷酸八钙（OCP）迅速转化为无定形磷酸钙（ACP），再由ACP转化为缺钙羟基磷灰石（DAP）和羟基磷灰石（HAP）的过程。DAP是ACP转化为HAP的非化学计量物质。反应温度对ACP转化为HAP的反应速率影响很大。在25 ℃时，形成纯相HAP需要24 h，而在60 ℃时，仅需5 min。温度对羟基磷灰石的粒径和形貌也有很大的影响。ACP转化为DAP的反应为二级反应，活化能为95 kJ/mol（22.7 kCal/mol），推测该转化反应为表面控制反应。(C)2001 Elsevier Science Ltd.保留所有权利。
The mechanism and kinetics of hydroxyapatite (HAP) precipitation from aqueous solution at the conditions of pH 10-11 and at calcium ion concentrations of more than 0.5 mol/I were investigated. The results show that the reaction undergoes the following process: transferring from octacalcium phosphate (OCP) to amorphous calcium phosphate (ACP) rapidly, and then from ACP to calcium-deficient hydroxyapatite (DAP) and HAP. DAP was the non-stoichiometric material that ACP converts to HAP. Reaction temperature greatly affects the reaction rate of the conversion from ACP to HAP. It takes about 24 h to form pure-phase HAP at 25 degreesC while it takes only 5 min at 60 degreesC. The temperature also has a great deal of influence on the particle size and morphology of precipitated hydroxyapatite. The reaction of transformation from ACP to DAP was second order and the activation energy was 95 kJ/mol (22.7 kCal/mol) and therefore it was inferred that the conversion reaction was a surface control process. (C) 2001 Elsevier Science Ltd. Ail rights reserved.