纳米CHAP的替换结构及其相变、吸F^-行为研究

Substitution Structure, Phase Tranversion and Absorbing F- Action of the CHAP in Nanoscale

用sol-gel法制备了不同CO32-掺量的碳羟磷灰石（CHAP）;采用FTIR、DTA、TG、XRD、TEM、晶粒密度测定、静态吸附等方法研究了CHAP的替换结构及其相变和吸F-行为.结果表明;CHAP属AB混合型替换结构;当WCO32-<3.34％时,随CO32-含量增加,RI增大,吸氟量减小,吸氟过程中有较强的优先吸附CO32-进入其晶格的能力,150～776℃脱CO32-相变为钙亏HAP,776℃时脱羟相变为TCP相;当WCO32-=3.34％时,RI达最大值,脱CO32-相变为正常配比HAP,在776℃时不发生脱羟相变;当3.34％<WCO32-≤7.52％时,随CO32-含量增加,RI减小,吸氟量增大,吸氟过程中有较强的优先吸附F-进入其晶格的能力而CO32-被交换出来,脱CO32-相变为钙盈HAP,在776℃时不发生脱羟相变;CHAP纳米晶有沿柱长方向的溶解行为,比纯HAP的吸氟量大2～3倍,表现出纳米尺度下的溶解-沉淀吸附效应.

The nano carbonate-containing hydroxyapatite (CHAP) with different 3 contents (WCO32-) was prepared by a sol-gel process. DTA, TG, XRD, FTIR, TEM, dynamic absorption test and crystalline density measurement were used to study substitution structure, phase tranversion and absorbing F- action of the CHAP. Test results indicate that the CHAP is with AB mixed-type substitution structure. When WCO32- <3.34%, RI increases and capacities absorbing F- decrease with the increasing of CO32- contents, and the CHAP has preferentially a tendency of absorbing CO32- to enter its lattice in absorbing F- process, and a phase tranversion from the CHAP to Ca-deficient HAP takes place at 150similar to776degreesC, then the HAP occurs dehydroxy phase tranversion at 776degreesC. When WCO32-=3,34%, RI has maximum value, a phase tranversion from the CHAP to Ca-stoichiometric HAP takes place at 150similar to776degreesC, so the dehydroxy phase tranversion of HAP can not occur at 776degreesC. When 3.34%< WCO32- <7.52%, RI decreases and capacities absorbing increase with the increasing of CO32- content, and the CHAP has preferentially a tendency of absorbing F- to enter its lattice and exchanging out CO32- in absorbing F- process, and a phase tranversion from the CHAP to Ca-surplus HAP takes place at 150similar to776degreesC, so the dehydroxy phase tranversion of HAP can not occur at 776degreesC. The nano CHAP crystals have a behavior of dissolving along crystal length, and 2-3 times capacities absorbing F- of the pure HAP, and show an effect of dissolving-precipitating adsorption in nanoscale.