Title Page
Contents
초록 7
Abstract 9
General introduction 15
Chapter Ⅰ. Literature review. 20
Ⅰ-1. The general context of plasma. 20
Ⅰ-2. Plasma classifications. 21
Ⅰ-3. Plasma reactors. 26
Ⅰ-3-1. Dielectric barrier discharge (DBD) 26
Ⅰ-3-2. Contact glow discharges (CGDE) 27
Ⅰ-3-3. Corona discharges 28
Ⅰ-3-4. Gliding arc discharge (GAD) 28
Ⅰ-4. Plasma gas-liquid phase interactions 32
Ⅰ-4-1. Acid-base reactions 32
Ⅰ-4-2. Oxidation Reactions 34
Ⅰ.5. Emerging organic contaminants studied in this dissertation 37
Chapter Ⅱ. Materials and Experimental Methods. 44
Ⅱ-1. Plasma Reactor 44
Ⅱ-2. Chemicals and reagents 45
Ⅱ-3. Chemical Analysis 45
Ⅱ-3-1. Hydroxyl radical (·OH) 45
Ⅱ-3-2. Detection and quantification of H₂O₂ 46
Ⅱ-3-3. Detection and quantification of O₃ 46
Ⅱ-3-4. Detection and quantification of NO₂⁻ and NO₃⁻ 47
Ⅱ-4. Eriochrome Black T degradation experiments 47
Ⅱ-5. Tetracycline degradation experiments 47
Ⅱ-6. Analytical Measurements 48
Ⅱ-7. Potassium Ferrate Synthesis 49
Chapter Ⅲ. Measurement of reactive species and effect of relative humidity. 51
Ⅲ-1. Generation of reactive species under different relative humidity conditions. 51
Ⅲ-1-1. Effect of relative humidity on RONS production 52
Ⅲ-2-1. Generation of ·OH 54
Ⅲ-2-2. Generation of H₂O₂ 59
Ⅲ-2-3. Generation of O₃ 59
Ⅲ-2-4. Generation of Nitrogen species 62
Ⅲ-2-5. Reactive species generated by GAD under optimum conditions 63
Ⅲ-3. pH variations of treated solution under GAD plasma 67
Chapter Ⅳ. Plasma treatment of Organic Pollutants 69
Ⅳ-1. Chapter Introduction 69
Ⅳ-2-1. Eriochrome Black T removal 70
Ⅳ-2-2. EBT mineralization 73
Ⅳ-3-1. Tetracycline removal 77
Ⅳ-3-2. Effect of TC initial concentration 77
Ⅳ-3-3. pH effect 80
Ⅳ-3-4. Effect of radical scavengers 83
Ⅳ-3-5. Tetracycline Mineralization efficiency 85
Ⅳ-3-6. Intermediates of Tetracycline and suggestion of a degradation pathway 87
Ⅳ-3-7. Toxicity evaluation 89
Chapter Ⅴ. Combination of plasma and homogenous catalysis for TC degradation 91
Ⅴ-1. Chapter introduction 91
Ⅴ-2. Influence of catalysts and combination process on GAD performance 91
Ⅴ-3. Effect of catalyst on TC without plasma discharge 95
Ⅴ-4. Effect of TC initial concentration. 96
Ⅴ-5. Optimization of catalyst dosage: and treatment time: Ferrate, Fe²⁺, Fe³⁺ and PS 99
Ⅴ-6. Removal efficiency of plasma catalysis in presence of Dimethyl Sulfoxide 102
Ⅴ-7. Effect of scavengers on TC removal by plasma catalysis 104
Conclusion 110
References 123
Table 1. Primary reactions in non-thermal plasma discharge. 25
Table 2. comparison of non-thermal plasmas applied for the removal of organic contaminants from aqueous solutions. 30
Table 3. The rate constants for OH·radical and ozone through direct reactions with selected organic and inorganic compounds in water. 35
Table 4. Main reactions taking place in air and oxygen plasma discharge. 36
Table 5. Analytical conditions of LC/MS/MS detection and analysis 48
Figure 1. Different classification of plasma discharges 26
Figure 2. a) Experimental set up. b) photo of O2 plasma. c) photo of air plasma. HT=15 kV. Flow=13 L/min. 44
Figure 3. Chromatogram of HCHO samples detected during plasma treatment. 53
Figure 4. Amount of hydroxyl radical (·OH) generated in DMSO under plasma discharge a) in Oxygen b) in air with different Relative Humidity rates. 55
Figure 5. Evolution of formaldehyde (HCHO) concentration under different feed gas. initial concentration 50 μmole/L 56
Figure 6. HCHO measured in treated samples with and without DMSO in Gliding Arc discharge in a) O2; b) Air. Initial concentrations: HCHO, 45 μmol/L; DMSO, 230 umol /L. 58
Figure 7. Concentration of hydrogen peroxide H₂O₂ as function of the gas relative humidity: a) in O2; b) in air. 60
Figure 8. Concentration of hydrogen peroxide O₃ as function of the gas relative humidity: a) in O₂; b) in air. 61
Figure 9. Concentration of a) nitrite (NO₂⁻) and b) nitrate (NO₃⁻) as function of air relative humidity. 62
Figure 10. Concentrations of reactive species generated in plasma: a)·OH; b) H₂O₂ ; c) NO₂⁻; d) NO₃⁻. 64
Figure 11. pH evolution during plasma discharge on DMSO. (Initial pH~6.0.8) 67
Figure 12. decolorization rate of EBT under different treatment conditions Initial concentration 100 mg/L. RH~30%. 71
Figure 13. EBT decolorization kinetics Initial concentration 100 mg/L. RH~30%. 72
Figure 14. treated samples of EBT after plasma treatment. Initial concentration 100 mg/L. RH~30%. Air plasma, flow rate=13 L/min. 72
Figure 15. comparison of EBT decolorization rates under various plasma discharge parameters after 30 minutes of plasma discharge. RH 30%, initial concentration 100 mg/L 73
Figure 16. Total Organic Carbon (TOC) of EBT treated in O₂ and air plasma. 74
Figure 17. Proposed degradation pathway for the mineralization of Eriochrome black T by plasma process. 75
Figure 18. Effect of TC initial concentration on degradation rate depending on plasma gas. a) O₂; b) air. (V=70 mL. Flow=13 L/min.). 79
Figure 19. evolution of pH during plasma treatment of TC solutions prepared at different initial pH value: a) O₂; b) air. ([TC]=10 mg/L. V=70 mL. Flow=13 L/min.). 81
Figure 20. a) Removal of TC after during plasma treatment in function of initial pH value of TC solutions. b) TC chemical structure and pKa of each active site in the molecule. ([TC]₀=10 mg/L. V=70... 82
Figure 21. Influence of radical scavenger presence on TC removal . a) O₂; b) air. ([TC]=20 mg/L. V=70 mL. Flow=13 L/min). 84
Figure 22. Removal of Total Organic Carbon (TOC) in TC solutions under plasma treatment a) O₂; b) air. (V=70 mL. Flow=13 L/min.). 86
Figure 23. a) Q-TOF LC/MS/MS peak area-time profile of degradation product 87
Figure 23. b) Proposed degradation pathway for TC treated by GAD plasma. 88
Figure 24. Toxicity evaluation of TC and its degradation intermediates by T.E.S.T program. 90
Figure 25. Influence of catalysts on the efficiency of GAD plasma reactor for TC removal: degradation (a) and mineralization (b) TC initial concentration: 50 mg/L. catalyst: 50 g. Applied voltage: 15 kV. Air... 92
Figure 26. Effect of catalysts on TC removal without plasma discharge. TC initial concentration: 50 mg/L. catalyst: 50 g. Applied voltage: 15 kV. Air flow rate: 13 L/min. 95
Figure 27. Effect of TC initial concentration. catalyst: 50 g. Applied voltage: 15 kV. Air flow rate: 13 L/min. 98
Figure 28. Effect of catalyst dose in function of plasma treatment time. TC initial concentration: 50 mg/L. Applied voltage: 15 kV. Air flow rate: 13 L/min. 101
Figure 29. Removal efficiency of plasma catalysis in presence of DMSO treatment time: 15 minutes. TC initial concentration: 50 mg/L. Catalyst: 30 mg/L 103
Figure 30. Effect of reactive oxygen species on TC degradation in GAD plasma reactor in the presence of salicylic acid as electrons scavenger; Tert-Butyl TBA as OH scavenger; and p-Benzoquinone p-BQ as... 105
Figure 31. Influence of reactive oxygen species (ROS) on TC degradation in GAD plasma reactor in the presence of scavengers. TC initial concentration: 50 mg/L. Applied voltage: 15 kV. Air flow rate: 13 L/min. 106
Figure 32. Influence of reactive oxygen species on TC degradation in GAD plasma reactor in the presence of EtOH as persulfate scavenger; Tert-Butyl TBA as OH scavenger; and p-Benzoquinone p-BQ as... 107