A systematic research was performed about diffusion kinetics of adsorbing F^- dissolved in water for carbonate hydroxyapatite （CHAP） from the natural hydroxyapatite which was modified by adulterating with CO3^2-. Th...A systematic research was performed about diffusion kinetics of adsorbing F^- dissolved in water for carbonate hydroxyapatite （CHAP） from the natural hydroxyapatite which was modified by adulterating with CO3^2-. The result shows that the speed of F^- adsorption is controlled by membrane diffusion when F^- concentration is relatively low, which is expressed by the kinetic equation of diffusion Q=0.0005（Ci-C）（t-ti）＋0.3967, or by vacancy diffusion when F^- concentration is relatively high, which is expressed by the kinetic equation of diffusion In[C（o, t）]=8.4718-0.5048Int. Based on the feature of CHAP for adsorbing F^- dissolved in water and its special channel of the structure of CO3^3- modified hydroxyapatite, models of vacancy diffusion and membrane diffusion were established.展开更多
In this study, X-ray diffraction （XRD）, Fourier transform infrared spectrometer （FTIR） together with Scanning probe microscopy （SPM） were used to characterize the structure and morphology of the complexes, where...In this study, X-ray diffraction （XRD）, Fourier transform infrared spectrometer （FTIR） together with Scanning probe microscopy （SPM） were used to characterize the structure and morphology of the complexes, where the hydrobiotites （Xinfiang） were modified by single-chain surfactants octyltrimethylammonium bromide （OTMA） and octadecyltrimethylammonium bromide （ODTMA）. XRD patterns showed that the structure of complexes was significantly influenced by the surfactant concentration and the alkyl chain length, because obvious changes took place in the basal spacing. Furthermore, according to the XRD results, several arrangements of surfactant molecules within the hydrobiotite interlayer space were deduced. The FTIR spectrum indicated that the surfactant contents in complexes dramatically increased with the alkyl chain length. The SPM micrographs demonstrated that the surfaces of complexes prepared at lower surfactant concentration were relatively flat compared with that prepared at higher concentration, while those with higher surfactant concentration had much steeper surface due to the alkyl chain length. It was concluded that structure and morphology of surfactant/hydrobiotite complexes depend not only on the surfactant concentration, but also strongly on the surfactant species.展开更多
基金the key scientific foundation(No.2001Z20004)the Hubei Provincial Department of Education and the natural science foundation(2005ABA024)
文摘A systematic research was performed about diffusion kinetics of adsorbing F^- dissolved in water for carbonate hydroxyapatite （CHAP） from the natural hydroxyapatite which was modified by adulterating with CO3^2-. The result shows that the speed of F^- adsorption is controlled by membrane diffusion when F^- concentration is relatively low, which is expressed by the kinetic equation of diffusion Q=0.0005（Ci-C）（t-ti）＋0.3967, or by vacancy diffusion when F^- concentration is relatively high, which is expressed by the kinetic equation of diffusion In[C（o, t）]=8.4718-0.5048Int. Based on the feature of CHAP for adsorbing F^- dissolved in water and its special channel of the structure of CO3^3- modified hydroxyapatite, models of vacancy diffusion and membrane diffusion were established.
基金NSFC (No. 40502008)Sichuan Province Application and Basic Research Project (No. 05JY029-008)
文摘In this study, X-ray diffraction （XRD）, Fourier transform infrared spectrometer （FTIR） together with Scanning probe microscopy （SPM） were used to characterize the structure and morphology of the complexes, where the hydrobiotites （Xinfiang） were modified by single-chain surfactants octyltrimethylammonium bromide （OTMA） and octadecyltrimethylammonium bromide （ODTMA）. XRD patterns showed that the structure of complexes was significantly influenced by the surfactant concentration and the alkyl chain length, because obvious changes took place in the basal spacing. Furthermore, according to the XRD results, several arrangements of surfactant molecules within the hydrobiotite interlayer space were deduced. The FTIR spectrum indicated that the surfactant contents in complexes dramatically increased with the alkyl chain length. The SPM micrographs demonstrated that the surfaces of complexes prepared at lower surfactant concentration were relatively flat compared with that prepared at higher concentration, while those with higher surfactant concentration had much steeper surface due to the alkyl chain length. It was concluded that structure and morphology of surfactant/hydrobiotite complexes depend not only on the surfactant concentration, but also strongly on the surfactant species.
