FTIR study of adsorption of CO2 on nonstoichiometric calcium hydroxyapatite
FTIR study of adsorption of CO2 on nonstoichiometric calcium hydroxyapatite
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DOI：
10.1021/la980339n
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发表时间：
1998-11-10
期刊：
影响因子：
3.9
通讯作者：
Ishikawa, T
中科院分区：
文献类型：
--
作者：
Cheng, ZH;Yasukawa, A;Ishikawa, T
对沉淀法合成的不同Ca/P原子比的羟基磷灰石钙(CaHAP)颗粒的表面进行了表征，并主要通过FTIR阐明了25℃下CaHAP对CO2的吸附机理。当Ca/P=1.6时，表面P-OH基团的数量最大，而在相同Ca/P时，不可逆吸附的CO2数量最小。这表明表面P-OH基团不仅是CO2的可逆吸附位点，而且还干扰CO2的不可逆吸附。由 H2O 和 CO32- 产生的红外谱带出现在 CO2 吸附上，并且随着吸附量的增加而增强。随着时间的推移，物理吸附的CO2转化为CO32-离子。这些结果表明，CO2的不可逆吸附是通过CO2与表面OH-的反应进行的：2OH(-) + CO2 --> CO32- + H2O。
The surfaces of calcium hydroxyapatite (CaHAP) particles with different Ca/P atomic ratios, synthesized by the precipitation method, were characterized and the adsorption mechanism of CO2 on CaHAP at 25 degrees C was elucidated mainly by FTIR. The number of surface P-OH groups was maximum at Ca/P = 1.6 while the quantity of irreversibly adsorbed CO2 was minimum at the same Ca/P. This indicates that the surface P-OH groups not only are the reversible adsorption sites for CO2 but also interfere with the irreversible adsorption of CO2. IR bands due to H2O and CO32- appeared on CO2 adsorption and were intensified by increasing the adsorbed amount. The physisorbed CO2 was converted into CO32- ions with the course of time. These results demonstrated that the irreversible adsorption of CO2 progresses via the reaction of CO2 with surface OH-: 2OH(-) + CO2 --> CO32- + H2O.