Effects of Surface Dissolution and Hydrogen Peroxide Deco,position on 2-Chlorophenol Degradation in α-FeOOH/H2O2 Process
| Autor: | Huang, Hsu-Hui, 黃旭輝 |
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| Rok vydání: | 1998 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 86 Gogthite is among the components of the subsurface mineral and plays an important role in the chemical remediation of contaminated soil. The treatment of 2-chlorophenol (2-CP) in the a-FeOOH/H2O2 Process has been investigated. This research is divided into three parts, including the studies of goethite surface dissolution, H2O2 decomposition and oxidation mechanism of 2-CP. The dissolution of goethite is substantially controlled by the detachment of the surface Fe center. Empirical rate equations have been showed with the related factors. The dissolution rate is enhanced markedly by oxalate and ascorbate. Different mechanisms for ligand (e.g.oxalate) and reductant (e.g.ascorbate) with goethite make the surface Fe(III) dissolve into cation Fe3+ and Fe2+, respectively. Kinetics of H2O2 has been investigated in the presence of goethite, and proceed with a first order relationship with respect to the H2O2 concentration. This kinetic model allows for a fairly good correlation of the experimental data. The dependence of the rate constant on PH is determined experimentally and explained in terms of the different structure of the surface active sites. The process toward 2-CP degradation is effective at acidic PH, whereas negligible at neutral PH and above. The oxidation rate of 2-CP is correlated with reductive dissolution(Fe2+ dissolution) rate at various dosages of goethite. The near linear relationship and the stoichiometric ratio indicate that the oxidation rate of 2-CP is surface-controlled. A probable mechanism has been suggested for the decomposition process, and implies that not contamination itself but its intermediate species would effect the degradation rate. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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