Title Page
ABSTRACT
Contents
1. Introduction 11
2. Removal of triclosan from aqueous solution via adsorption by kenaf-derived biochar: its adsorption mechanism study via spectroscopic and experimental approaches 15
2.1. Materials and methods 15
2.1.1. Materials 15
2.1.2. Preparation of kenaf-derived biochar 15
2.1.3. Characterization of biochar 16
2.1.4. Triclosan removal experiment 17
2.1.5. Data analysis 18
2.2. Results and discussion 20
2.2.1. Characterization of kenaf biochar 20
2.2.2. Effect of pyrolysis temperature on triclosan adsorption 29
2.2.3. Effect of adsorption time on triclosan adsorption and kinetic model analysis 31
2.2.4. Effect of initial concentration on triclosan adsorption and isotherm model analysis 33
2.2.5. Effect of solution chemistry on the adsorption of triclosan by KNF-750 37
2.2.6. Effect of adsorbent dosage and regeneration on the adsorption of triclosan by KNF-750 39
2.2.7. Effect of reaction temperature on triclosan adsorption and thermodynamic analysis 41
2.2.8. Triclosan adsorption mechanism by KNF-750 42
3. Adsorption of phenol on kenaf-derived biochar: Studies on physicochemical and adsorption characteristics and mechanism 47
3.1. Materials and methods 47
3.1.1. Preparation of Materials 47
3.1.2. Characterization of biochar 47
3.1.3. Phenol removal experiment 48
3.2. Results and discussion 50
3.2.1. Properties of biochar derived from kenaf 50
3.2.2. Effect of pyrolysis temperature on phenol adsorption 59
3.2.3. Kinetic phenol adsorption to KNF-750 and model analysis 61
3.2.4. Equilibrium phenol adsorption to KNF-750 and isotherm model analysis 64
3.2.5. Effect of phenol adsorption on reaction temperature and its thermodynamic analysis 67
3.2.6. Effect of solution chemistry on phenol adsorption 68
3.2.7. Effect of adsorbent dose and regeneration adsorption of phenol by KNF-750 71
3.2.8. Mechanism of phenol adsorption by KNF-750 73
4. Removal of triclosan from aqueous solution using biochar derived from seed shell of Aesculus turbinata 77
4.1. Materials and methods 77
4.1.1. Chemicals 77
4.1.2. Preparation of biochar derived from Aesculus turbinata seed shell 77
4.1.3. Characterization of biochar 77
4.1.4. Triclosan Removal Experiment 78
4.2. Results and discussion 79
4.2.1. Characterization of Aesculus turbinata seed shell pyrolyzed under different temperatures 79
4.2.2. Effect of pyrolysis temperature on the triclosan adsorption of Aesculus turbinata seed shell-derived biochar 84
4.2.3. Adsorption kinetics 85
4.2.4. Adsorption isotherm 88
4.2.5. Adsorption thermodynamic parameters 91
4.2.6. Effect of pH on the adsorption of triclosan 92
4.2.7. Effect of adsorbent dosage on the adsorption of triclosan 94
5. Conclusion 95
Bibliography 96
Summary in Korean 116
Table 2.1. Elemental composition, specific surface area, pore structure, and pH of kenaf-derived biochar at different temperatures. 23
Table 2.2. The yield of biochars and the pyrolysis condition for biochar production 27
Table 2.3. Elemental composition obtained from X-ray fluorescence spectrometer and cation eluted from kenaf-derived biochar at different temperatures 28
Table 2.4. Parameter of kinetic models obtained by fitting the model to the adsorption of triclosan onto KNF-750 regarding reaction times 33
Table 2.5. Parameter obtained by fitting the model to the triclosan adsorbed onto KNF-750, under different triclosan concentration in aqueous phases at equilibrium (Qm: the maximum adsorption...[이미지참조] 35
Table 2.6. Maximum adsorption capacity of triclosan by various carbon-based adsorbents. 35
Table 2.7. Enthalpy, entropy, and Gibb's free energy for the adsorption of triclosan by KNF-750 42
Table 3.1. Elemental composition, specific surface area, and pore structure of KNF-BC according to pyrolysis temperature. 53
Table 3.2. Cations and anions eluted from kenaf-derived biochar at different temperatures 55
Table 3.3. Parameters obtained by fitting kinetic models to the adsorption of phenol by KNF-750 according to different reaction times (qe: the amount of phenol adsorbed onto KNF-750 at equilibrium...[이미지참조] 62
Table 3.4. Parameters obtained by fitting adsorption equilibrium models to the equilibrium data of phenol adsorbed to KNF-750 according to various initial concentrations (Qm: the maximum adsorption...[이미지참조] 64
Table 3.5. Comparison of maximum phenol adsorption capacities of various activated carbon and biochar with specific experimental conditions for obtaining the maximum phenol adsorption capacity... 65
Table 3.6. Enthalpy (△H°), entropy (△S°), and Gibbs free energy (△G°) as parameters in thermodynamic adsorption of phenol to KNF-750 68
Table 4.1. Specific surface area, pore structure, and elemental composition of Aesculus turbinata seed shell-derived biochar under different temperatures. 82
Table 4.2. Parameters of kinetic models obtained by fitting the model to triclosan adsorption data using SAT-300 at different reaction times (qe: the amount of triclosan adsorbed onto SAT-300 at...[이미지참조] 86
Table 4.3. Parameter of kinetic models obtained by fitting the model to the adsorption of triclosan on SAT-300 under different triclosan concentration in aqueous phases at equilibrium (Qm: the...[이미지참조] 89
Table 4.4. Maximum adsorption capacity of triclosan by various types of adsorbents 90
Table 4.5. Enthalpy, entropy, and Gibb's free energy for the adsorption of triclosan by SAT-300 (initial triclosan concentration: 100 mg/L; adsorbent dose: 1.67 g/L; reaction time: 12 h; reaction... 92
Fig. 2.1. FE-SEM images of biochar derived from kenaf at different temperatures. a) KNF-NT, b) KNF-300, c) KNF-450, d) KNF-600, and e) KNF-750; f) digital image of KNF-750. 24
Fig. 2.2. (a) Pore size distribution and (b) accumulative pore volume for non-treated, KNF-300, KNF-450, KNF-600, and KNF-750 obtained by quenched solid density functional theory 25
Fig. 2.3. Thermogram and differential thermogram obtained via thermogravimetric analysis of kenaf between 30 and 780℃ 26
Fig. 2.4. Determination of point of zero charges (pHpzc) of the non-treated, KNF-300, KNF-450, KNF-600, and KNF-750 by measuring the zeta potential of the kenaf biochar in the range of pH 1.8–6.2[이미지참조] 26
Fig. 2.5. Fourier transform infrared spectroscopy spectra of biochar derived from kenaf at different temperature (Non-treated, 300, 450, 600, and 750℃) 28
Fig. 2.6. Effect of pyrolysis temperature on the triclosan adsorption capacity of kenaf-derived biochars 30
Fig. 2.7. Kinetic adsorption results for triclosan adsorption by KNF-750 and model fits using pseudo-first order and pseudo-second order model 32
Fig. 2.8. Intraparticle diffusion (IPD) model fits to kinetic adsorption data (time½ versus adsorbed triclosan)[이미지참조] 32
Fig. 2.9. Adsorption isotherm data for triclosan adsorption by KNF-750 and model fits using Langmuir, Freundlich, and D-R models 34
Fig. 2.10. Effects of solution pH on the adsorption of triclosan on KNF-750 and the solubility of triclosan 38
Fig. 2.11. Effects of the presence of anions and humic acid on the triclosan adsorption by KNF-750 39
Fig. 2.12. Effects of dosage of KNF-750 on the adsorption capacity of KNF-750 and removal percentage of triclosan 40
Fig. 2.13. Adsorbed triclosan amount of KNF-750 regenerated using deionized water 41
Fig. 2.14. Fitted SAXS patterns of (a) KNF-750 and (b) triclosan adsorbed KNF-750. 44
Fig. 2.15. FTIR spectra of (a) KNF-750 and (b) triclosan adsorbed KNF-750. 44
Fig. 2.16. Peak at 284.6 eV of C1s spectra and its optimized peak by XPSPeak 4.1 (a) KNF-750, (b) tri-KNF-750 45
Fig. 2.17. XPS spectra of KNF-750 and triclosan adsorbed KNF-750 (tri-KNF-750); (a) C1s of KNF-750, (b) C1s of tri-KNF-750, (c) O1s of KNF-750, (d) O1s of tri-KNF-750, (e) Cl2p of KNF-... 46
Fig. 3.1. FE-SEM images of pyrolyzed kenaf at different temperatures: (a) Untreated kenaf; and KNF-BC at (b) 300℃, (c) 450℃, (d) 600℃, and (e) 750℃ (KNF-750). (f) Digital image of KNF-750. 54
Fig. 3.2. (a) Pore size distribution and (b) accumulative pore volume for untreated, KNF-300, KNF-450, KNF-600, and KNF-750 obtained by quenched solid density functional theory 56
Fig. 3.3. Determination of point of zero charges (pHpzc) of the untreated, KNF-300, KNF-450, KNF-600, KNF-750 by measuring the zeta potential of the KNF-BC[이미지참조] 57
Fig. 3.4. Fourier transform infrared spectroscopy spectra of kenaf-derived biochar at different temperatures (untreated, 300, 450, 600, and 750℃) 58
Fig. 3.5. Thermogram and differential thermogram obtained from thermogravimetric analysis of kenaf at temperatures from 30 to 900℃ 59
Fig. 3.6. Amounts of phenol adsorbed to kenaf-derived biochar pyrolyzed under different temperatures 61
Fig. 3.7. Kinetic adsorption results for phenol adsorption by KNF-750 and model fits. (a) pseudo- first order (PFO) and pseudo-second order (PSO) model fits and (b) intraparticle diffusion (IPD) model fit 63
Fig. 3.8. Adsorption isotherm data for phenol adsorbed on KNF-750 and model fits using Langmuir and Freundlich models (Ceq : the concentration of phenol in the aqueous solution at equilibrium (mg/L))[이미지참조] 65
Fig. 3.9. Effects of (a) solution pH, (b) NaCl molar concentration (ionic strength), (c) presence of cation, anion, and humic acid on the phenol adsorption by KNF-750 70
Fig. 3.10. Effects of KNF-750 dosage on the adsorption of phenol 72
Fig. 3.11. Amount of phenol adsorption on regenerated KNF-750 using deionized water, HCl, and NaOH 73
Fig. 3.12. Fourier transform infrared spectra of KNF-750 before and after phenol adsorption 75
Fig. 3.13. FE-SEM images of surface morphologies of KNF-750 (a) before and (b) after adsorption 75
Fig. 3.14. XPS spectra of C1s (a, b) and O1s (c, d) for KNF-750 before and after phenol adsorption. (a, c) C1s and O1s of KNF-750 before phenol adsorption and (b, d) C1s and O1s of KNF-750 after... 76
Fig. 3.15. Schematic diagram of phenol adsorption mechanism 76
Fig. 4.1. FE-SEM images of biochar derived from Aesculus turbinata seed shells at different temperatures. a) Non-treated seed shell, b) biochar derived from seed shell at 300℃ (SAT-300), c)... 81
Fig. 4.2. (a) Fourier transform infrared spectroscopy spectra of biochar derived from Aesculus turbinata seed shell at different temperatures (Non-treated, 300, 400, 500, 600, and 700℃); (b)... 83
Fig. 4.3. Effect of pyrolysis temperature on the triclosan adsorption capacity of Aesculus turbinata seed shell-derived biochar (initial triclosan concentration: 100 mg/L; adsorbent dose: 1.67 g/L;... 85
Fig. 4.4. (a) Kinetic adsorption results for triclosan adsorption by SAT-300 and model fit using pseudo-first-order and pseudo-second-order models; (b) Intraparticle diffusion (IPD) model fitted to... 87
Fig. 4.5. Adsorption isotherm data for triclosan adsorption by SAT-300 and model fitting using Langmuir and Freundlich models (initial triclosan concentration: 5-100 mg/L; adsorbent dose: 0.67... 89
Fig. 4.6. Effects of solution pH on the adsorption of triclosan by SAT-300 (initial triclosan concentration: 100 mg/L; adsorbent dose: 1.67 g/L; initial pH: 3-11; reaction time: 12 h; reaction... 93
Fig. 4.7. Effects of SAT-300 dose on its adsorption capacity and triclosan removal percentage (initial triclosan concentration: 100 mg/L; adsorbent dose: 1.67-10 g/L; reaction time: 12 h; reaction... 94