| 摘要 | 第5-7页 |
| Abstract | 第7-8页 |
| Chapter 1 Introduction | 第17-55页 |
| 1.1 Arsenic element in Nature | 第17-36页 |
| 1.1.1 Arsenic emission | 第18-20页 |
| 1.1.2 Pyrometallurgical operation | 第20页 |
| 1.1.3 Hydrometallurgical operations | 第20-22页 |
| 1.1.4 Main arsenic species | 第22-23页 |
| 1.1.5 Arsenic toxicity | 第23-24页 |
| 1.1.6 Fixation of arsenic | 第24-26页 |
| 1.1.7 Arsenic removal processes with iron precipitation | 第26-27页 |
| 1.1.8 Arsenical ferrihydrite | 第27-36页 |
| 1.2 Oxidation from As (Ⅲ) to As (Ⅴ) | 第36-43页 |
| 1.2.1 Ozone oxidation | 第38-39页 |
| 1.2.2 Ozone reaction | 第39-41页 |
| 1.2.3 Effect of pH on ozonation | 第41-42页 |
| 1.2.4 Effect of temperature on ozonation | 第42-43页 |
| 1.2.5 Catalysts for decomposition of ozone | 第43页 |
| 1.3 Crystallization and precipitation | 第43-52页 |
| 1.3.1 Supersaturation | 第44-46页 |
| 1.3.2 Nucleation | 第46-49页 |
| 1.3.3 Crystal growth or secondary nucleation | 第49-50页 |
| 1.3.4 Two-step mechanism of nucleation of crystals in solution | 第50-51页 |
| 1.3.5 LaMer Mechanism | 第51页 |
| 1.3.6 Ostwald's rule of stages | 第51-52页 |
| 1.4 Research aim and objectives | 第52-55页 |
| Chapter 2 Arsenic (Ⅲ) Oxidation by Ozone and Ferric Ion | 第55-71页 |
| 2.1 Introduction | 第55-57页 |
| 2.2 Experimental | 第57-59页 |
| 2.2.1 Chemicals | 第57页 |
| 2.2.2 Oxidation of As (Ⅲ) by ozone | 第57-58页 |
| 2.2.3 Experimental procedure | 第58页 |
| 2.2.4 Separation of As (Ⅲ) and As (Ⅴ) | 第58-59页 |
| 2.2.5 Determination of arsenic concentration | 第59页 |
| 2.2.6 Precipitation process | 第59页 |
| 2.3 Results and Discussion | 第59-69页 |
| 2.3.1 Effect of reaction time | 第59-62页 |
| 2.3.2 Effect of temperature and Fe~(3+) | 第62-64页 |
| 2.3.3 Oxidation of As(Ⅲ) to As(Ⅴ) by air | 第64-65页 |
| 2.3.4 The temperature of 70 ℃ versus 90 ℃ for precipitation of ferric arsenate | 第65-69页 |
| 2.4 Summary | 第69-71页 |
| Chapter 3 Fixation of Arsenic by Complex Precipitate of Scorodite andFerrihydrite | 第71-91页 |
| 3.1 Introduction | 第71-73页 |
| 3.2 Experimental | 第73-74页 |
| 3.2.1 Materials | 第73页 |
| 3.2.2 Experimental apparatus | 第73页 |
| 3.2.3 Experimental procedure | 第73-74页 |
| 3.2.4 Leaching test | 第74页 |
| 3.2.5 Analysis | 第74页 |
| 3.3 Results and discussion | 第74-90页 |
| 3.3.1 Precipitation of ferric arsenate at pH 2 | 第74-78页 |
| 3.3.2 Formation of crystalline scorodite in a two-stage precipitation (pH 2-3) | 第78-81页 |
| 3.3.3 Fixation of arsenic via improving pH of solution from 2 to 4 | 第81-85页 |
| 3.3.4 Leaching test of produced solids | 第85-87页 |
| 3.3.5 Behavior of iron during precipitation process for arsenic removal | 第87-90页 |
| 3.4 Summary | 第90-91页 |
| Chapter 4 Two-Stage Precipitation/Coprecipitation Process for ArsenicRemoval | 第91-103页 |
| 4.1 Introduction | 第91-93页 |
| 4.2 Experimental | 第93-94页 |
| 4.2.1 Material | 第93-94页 |
| 4.2.2 Experimental procedure | 第94页 |
| 4.3 Result and discussion | 第94-101页 |
| 4.3.1 Two-stage precipitation of ferric arsenate in wastewater | 第94-97页 |
| 4.3.2 Precipitation of As from waste water by adding Fe~(2+) (Fe (Ⅱ)/As (Ⅴ)) withozone oxidation | 第97-101页 |
| 4.4 Summary | 第101-103页 |
| Chapter 5 Conclusions and Recommendations | 第103-107页 |
| 5.1 Overview | 第103页 |
| 5.2 Conclusions | 第103-105页 |
| 5.2.1 Arsenic (Ⅲ) oxidation by ozone and effect of ferric ion on ozonation | 第103-104页 |
| 5.2.2 Complex precipitate containing scorodite and ferrihydrite | 第104-105页 |
| 5.2.3 Two-stage precipitation/ coprecipitation process for arsenic removal | 第105页 |
| 5.3 Perspectives | 第105-107页 |
| References | 第107-127页 |
| Acknowledgement | 第127-129页 |
| Curriculum Vitae (With Publications) | 第129-130页 |
