Phosphate sorption on monohydrocalcite
Phosphate sorption on monohydrocalcite
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DOI：
10.2465/jmps.101021a
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发表时间：
2011-04
影响因子：
0.7
通讯作者：
S. Yagi;K. Fukushi
中科院分区：
文献类型：
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作者：
S. Yagi;K. Fukushi
根据3种Mg浓度下的吸附等温线，分析了磷酸盐在一水方解石（CaCO 3·H2O; MHC）上的吸附行为和机理。已知MHC是亚稳态的，并且它迅速转化为方解石或文石。但少量磷酸盐（30 μM）可显著抑制MHC的转化。在低磷负荷下，吸附等温线符合Langmuir吸附等温线。在低磷负荷条件下，磷的吸附方式主要是吸附在MHC表面。Langmuir吸附参数表明，MHC的质量基础上的吸附容量显着高于文石和方解石。在较高的磷酸盐负荷，所获得的等温线的斜率迅速增加，偏离的朗缪尔等温线。低Mg浓度的等温线的斜率高于高Mg浓度的等温线的斜率。据文献记载，镁抑制磷酸钙矿物质的形成。在这项研究中进行的饱和度计算表明，反应的解决方案变得相对于无定形磷酸钙在相应的高磷酸盐负载过饱和。在较高的磷酸盐负荷下的磷酸盐吸附模式被认为对应于次生磷酸钙矿物的形成。
The sorption behavior and the mechanism of phosphate sorption on monohydrocalcite (CaCO3·H2O; MHC) were analyzed on the basis of sorption isotherms corresponding to three Mg concentrations. MHC is known to be metastable, and it quickly transforms to calcite or aragonite. However, a small amount of phosphate (30 μM) can significantly inhibit the transformation of MHC. At low phosphate loading, the sorption isotherms obtained are Langmuir adsorption isotherms. The mode of phosphate sorption is most likely to be adsorption on MHC surface at the low phosphate loadings. The Langmuir parameters indicate that the mass basis sorption capacity of MHC is significantly higher than those of aragonite and calcite. At higher phosphate loadings, the slopes of the obtained isotherms rapidly increase and deviate from that of a Langmuir isotherm. The slopes of the isotherms for low Mg concentrations are higher than those for high Mg concentrations. It is well documented that Mg inhibits the formation of calcium phosphate minerals. The saturation calculations performed in this study showed that the reacted solutions become supersaturated with respect to amorphous calcium phosphate at corresponding high phosphate loadings. The mode of phosphate sorption at higher phosphate loadings is considered to correspond to the formation of secondary calcium phosphate minerals.