Kinetic research on the sorption of aqueous lead by synthetic carbonate hydroxyapatite
| Autor: | Peng Wang, Yu Liu, Lei Yang, Mingsheng Peng, Huan-Yan Xu |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Environmental Engineering
Inorganic chemistry Carbonates Activation energy Management Monitoring Policy and Law Kinetic energy complex mixtures Water Purification Reaction rate symbols.namesake Reaction rate constant Waste Management and Disposal Arrhenius equation Toxicity characteristic leaching procedure Aqueous solution Chemistry Temperature Sorption General Medicine Hydrogen-Ion Concentration Kinetics Durapatite Lead symbols Adsorption Water Pollutants Chemical |
| Zdroj: | Journal of Environmental Management. 86:319-328 |
| ISSN: | 0301-4797 |
| Popis: | The sorption of aqueous lead on carbonate-hydroxyapatite (CHAp) is a complicated non-homogeneous solid/water reaction, which from the kinetic point of view has two stages. In the first stage, the reaction rate is so fast and the kinetic pathway so intricate that further research is required. In the second stage, the reaction rate slows down and the reaction process follows that of a first-order kinetic equation. Experimental results show that the relationship between the reaction rate constant k 1 and temperature T agrees with the Arrhenius equation, and that the activation energy of sorption ( E a ) is 11.93 kJ/mol and the frequency factor ( A ) is 2.51/s. The reaction rate constant k 1 increases with the Pb 2+ initial concentration and decreasing pH, but with increasing CHAp dosage. X-ray diffraction (XRD), scanning electron microscopy with energy dispersion spectrum (SEM-EDS) and toxicity characteristic leaching procedure (TCLP) tests indicate that the main sorption mechanism is dissolution-precipitation, in conjunction with surface sorption. |
| Databáze: | OpenAIRE |
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