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Statistics and complexity of wavefunction spreading in quantum dynamical systems
No full textWe consider the statistics of the results of a measurement of the spreading operator in the Krylov basis generated by the Hamiltonian of a quantum system starting from a specified initial pure state. We first obtain the probability distribution of the results of measurements of this spreading operator at a certain instant of time, and compute the characteristic function of this distribution. We show that the moments of this characteristic function are related to the so-called generalised spread complexities, and obtain expressions for them in several cases when the Hamiltonian is an element of a Lie algebra. Furthermore, by considering a continuum limit of the Krylov basis, we show that the generalised spread complexities of higher orders have a peak in the time evolution for a random matrix Hamiltonian belonging to the Gaussian unitary ensemble. We also obtain an upper bound in the change in generalised spread complexity at an arbitrary time in terms of the operator norm of the Hamiltonian and discuss the significance of these results. © The Author(s) 2025.TRUEsciescopu
Ni-supported in Tailored Silica Catalysts for Dry Reforming of Methane
No full textThe continuous dependence on and excessive use of fossil fuels has led to the emission of various greenhouse gases, causing serious environmental problems. Carbon dioxide (CO2) and methane (CH4) are considered the main drivers of climate change and global warming. While the atmospheric concentration of CO2 is much higher, CH4 has a significantly stronger greenhouse effect. Therefore, the need to efficiently convert these two gases into useful substances through chemical reactions has become increasingly important. Dry methane reforming (DRM) is an innovative technology that can simultaneously convert CH4 and CO2 into synthesis gas (H2 and CO). The process not only decreases greenhouse gas emissions but also enables the synthesis of environmentally friendly chemical products. Nickel (Ni)-based catalysts are mainly used in DRM processes due to their high activity and economic advantages. However, Ni-based catalysts have low resistance to coking and sintering, leading to catalyst deactivation during DRM process and significantly hindering their potential for industrial applications. Therefore, effective catalyst design is essential for process stability. In this study, we present two strategic approaches to enhance the performance of nickel catalysts supported on silica for dry methane reforming (DRM) reactions. Chapter 1 investigates the influence of the silica framework ligand length on the catalyst activity and stability. The catalysts were synthesized using silica framework precursors with C1~C4 carbon chain lengths, through a sequentially integrated sol-gel and re-precipitation method. The carbon chain length of the ligand influenced the reaction rate during the synthesis process and final physicochemical properties. The longest chain framework ligand (C4) formed small and uniform Ni particles and enhanced the interactions between Ni and silica. Also, it enhanced acid/base properties, resulting in improved catalyst performance. Chapter 2 explored an approach to control the chemical characteristics of the silica surface. To impart acidic and basic properties to the silica, it was synthesized by adjusting the molar ratio of tetraethoxysilane (TEOS) and 3-aminopropyltrimethoxysilane (APTES), followed by impregnation with nickel (Ni). The synthesized silica and Ni impregnated catalysts exhibited differences in porous structure, acidity/basicity, and Ni states depending on the molar ratio of the silica precursors. Among them, the catalyst with an intermediate ratio has the advantages of both TEOS and APTES-rich conditions, effectively overcoming the limitations of silica-based supports. Thus, the performance of Ni-based catalysts in DRM significantly improved. This research used two strategic approaches to improve silica supports and enhance the performance and stability of nickel catalysts in dry methane reforming (DRM) reactions. These strategies are expected to provide new directions for the design of efficient and sustainable silica-supported nickel catalysts for DRM.MasterAbstract ⅰ
Table of Contents ⅳ
List of figures ⅵ
List of tables ⅸ
Chapter 1. Tailoring Ni-SiO2 Catalysts for Dry Reforming of Methane:
Effect of Ligand length in Silica Framework Precursors 1
1.1. Introduction 2
1.2. Experimental 5
1.3. Results and discussion 9
1.4. Conclusions 39
Chapter 2. Design and Development of Ni-Supported Functionalized Silica Catalysts for
Dry reforming of Methane: Effects of Silica Precursors 41
2.1.1. Introduction 42
2.1.2. Experimental 45
2.1.3. Results and discussion 50
2.1.4. Conclusions 84
References 90
Curriculum Vitae 10
Differential Coaxial Coils for Frequency Independent Deep Magnetic Focusing on Implantable Devices
No full textMagnetic field focusing in longitudinal direction has been a missing link for three-dimensional synthesized magnetic focusing (3-D SMF). Deep magnetic focusing (DMF) by multiple coaxial coils, a sort of 3-D SMF, is firstly proposed in this paper, where magnetic field becomes maximum at the focal range in longitudinal direction. DMF is requisite for transcranial magnetic stimulation (TMS) and wireless power transfer (WPT). As the simplest DMF, a set of differential coils with opposite current direction is implemented. Optimum coil currents, coil radii, and coil distance are designed to provide with zero magnetic field at zero range and maximum magnetic field at a focal range. This DMF performance is found to be achieved with a penalty of peak magnetic field reduction. Experiments for the differential coils of diameters 10 cm and 5 cm with 3 cm gap showed 4 cm depth DMF within 6 cm diameter. Specific numbers of turns make the DMF be driven by only a single voltage source, which is firstly adopted in SMF. The frequency versatile DMF characteristic is experimentally verified for 60 Hz and 40 kHz, where 27mW is delivered to a focal point that is a demonstration for safer WPT of implantable devices. © 1963-2012 IEEE.FALSEsciescopu
Evaluation of Storage Stability and Applicability of Chlorine Dioxide Solution in Drinking Water Treatment
No full textPeroxisomal dysfunction in cardiac adipose tissue is involved in obesity-associated cardiac hypertrophy
No full textIntroduction
Cardiac adipose tissue, which directly interfaces with the myocardium and vasculature, has a pivotal role in obesity-related cardiovascular pathology through its metabolic activity. This tissue contributes to cardiac remodeling through its regulation of lipid metabolism. Among the key organelles involved, peroxisomes have a central role in lipid metabolism, yet their contribution to obesity-induced cardiac dysfunction remains poorly understood.
Objectives
This study investigated whether peroxisomal dysfunction in cardiac adipose tissue drives obesity-associated cardiac hypertrophy.
Methods
Using a high-fat diet (HFD)-induced obese rat model, we evaluated changes in cardiac adipose tissues, focusing on their browning capacity and metabolic functions. To investigate mechanistic effects, H9C2 cardiomyocytes were exposed either to fatty acids extracted from cardiac adipose tissues or conditioned medium derived from adipocytes treated with mitochondrial and peroxisomal inhibitors (Mdivi-1 or 10,12-tricosadiynoic acid).
Results
HFD-fed obese rats exhibited significant expansion of cardiac adipose tissues and cardiac hypertrophy, driven by impaired lipid metabolism and loss of browning capacity in cardiac fat associated with peroxisomal dysfunction. Treatment of H9C2 cardiomyocytes with conditioned medium from adipocytes with peroxisomal dysfunction induced collagen accumulation, increased expression of pro-inflammatory cytokines, and cellular hypertrophy, which recapitulates key pathological features observed in vivo.
Conclusion
Our findings demonstrate that peroxisomal dysfunction in cardiac adipose tissue drives lipid metabolic reprogramming and contributes to obesity-related cardiac hypertrophy. Targeting peroxisomal function in cardiac fat could be a novel therapeutic approach to mitigate obesity-induced cardiovascular remodeling.TRUEsciescopu
Dual functionality of carbazole-based phosphonic acid molecular additives realizes efficient hole transport layer-free perovskite light-emitting diodes
No full textTraditionally, perovskite light-emitting diodes (PeLEDs) have used complex and costly hole transport layers (HTLs), but these materials pose a significant challenge to commercialization due to their synthetic complexity and energy-intensive deposition processes. Eliminating the use of HTLs can effectively reduce manufacturing costs and simplify device production. Here, we present a simple method to achieve efficient HTL-free devices by exploiting the self-assembly property of carbazole-based phosphonic acid (PACz) molecules to address the issues of poor hole injection and charge imbalance in HTL-free PeLEDs. The results show that the self-assembly property and defect passivation effect of PACz molecules significantly improve the device performance. The self-assembly of some molecules on the ITO substrate creates hole-selective contacts and lowers the hole injection barrier. This facilitates hole injection and radiative recombination. Meanwhile, due to the interaction between P=O (and/or halide headgroup) and perovskite, some molecules incorporated in perovskite effectively passivate the uncoordinated Pb2+ and halide vacancies. As a result, efficient HTL-free PeLEDs were realized by incorporating PACz molecules into perovskites. © 2024 Elsevier B.V.FALSEsciescopu
Renyi reflected entropy and entanglement wedge cross section with cosmic branes in AdS/BCFT
No full textIn this study, we calculate the m-1 correction to the reflected entropy for two adjacent intervals on a half-infinite line within the AdS3/BCFT2 framework, where m is a Renyi index for a canonical purification. We utilize the doubling trick and compute the leading terms in the large central charge expansion of correlation functions in the holographic boundary conformal field theory (BCFT). In the corresponding anti-de Sitter (AdS) space with an end of the world brane, we analyze the entanglement wedge cross section, the dual counterpart of reflected entropy. This AdS/BCFT setup allows us to explore a richer set of phases in the entanglement wedge cross section. The m-1 correction in the holographic BCFT manifests as modifications in the entanglement wedge cross section induced by cosmic branes. For the adjacent intervals anchored to the boundary of BCFT, we show the duality between the entanglement wedge cross section with the backreaction from a cosmic brane and Renyi reflected entropy at all orders in m-1. Furthermore, by analyzing the entanglement wedge cross section for general adjacent intervals, we provide guidance for an & varepsilon; expansion of five-point functions in the holographic conformal field theory (CFT), where & varepsilon; is the rescaled conformal dimension by the central charge.FALSEsciescopu
Characterization of Catalyst Layer using Gas Diffusion Electrode Half-Cell system for Polymer Electrolyte Membrane Fuel Cell Hyeon Seung Jung
No full textGas diffusion electrode (GDE) half-cells were introduced for evaluating the oxygen reduction reaction in the polymer electrolyte membrane fuel cell field, allowing the evaluation of high current density regions, which were difficult to measure using a rotating disk electrode, with the actual catalyst layer used in practice. However, GDE involves immersing the catalyst layer directly in the electrolyte, which leads to electrolyte diffusion into the catalyst layer, often complicating accurate performance evaluation and measurement. Moreover, since previous studies and commercial products use catalyst-coated membranes (CCMs), evaluating half-cells with the membrane is crucial as it helps bridge the gap toward single-cell development.
This thesis introduces the half-electrode evaluation system (HEES), a novel GDE half-cell setup designed to evaluate CCMs under conditions that closely replicate full-cell operation. Electrochemical techniques, including polarization curves, cyclic voltammetry, CO stripping, and impedance spectroscopy, were applied with tailored protocols to evaluate ORR behavior and catalyst layer performance. The findings confirm that HEES provides detailed insights into electrode electrochemical characteristics, establishing it as an effective tool for bridging GDE half-cells and full-cell conditionsDoctorContent
Abstract ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ i
Content ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ ii
List of Figures ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ iv
List of Tables ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ vii
Chapter 1. Introduction ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 8
1.1 Background ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 8
1.1.1 The climate crisis․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 8
1.1.2 The polymer electrolyte membrane fuel cell ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 11
1.1.3 Research gap between catalyst and electrode level ․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 15
1.1.4 Gas diffusion electrode (GDE) half-cell system as evaluation tool ․․․․․․․ 20
1.2 Motivation and Objectives ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 26
1.2.1 Limitation of GDE half-cell ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 26
1.2.2 Objective ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 28
Chapter 2. Methods ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 32
2.1 Half Electrode Evaluation Systme (HEES) ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 32
2.1.1 Working electrode (WE) cartridge ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 32
2.1.2 Counter electrode (CE) and reference electrode (RE) ․․․․․․․․․․․․․․․․․․․․․․․․․ 33
2.1.3 Cell assembly ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 33
2.1.4 HEES system ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 34
2.2 Evaluation Protocols for HEES ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 39
2.3 Electrochemical catalyst layer characterization․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 42
2.3.1 Preparation of catalyst layer ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 42
2.3.2 HEES setup ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 43
2.3.3 Determination of the electrochemical surface area (ECSA) ․․․․․․․․․․․․․․․․․․ 44
2.3.4 CO displacement and stripping ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 45
2.3.5 Proton diffusion resistance ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 46
2.4 Electrochemical impedance spectroscopy (EIS) and distribution of realaxation time
(DRT) method ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 47
Chapter 3. EVALUATION OF GAS DIFFUSION ELECTRODE USING HALF ELECTRODE
EVALUATION SYSTEM ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 51
3.1 Introduction ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 51
3.2 Experimental ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 51
3.3 Results and Discussions ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 54
3.4 Summary ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 68
Chapter 4. EVALUATION OF CATALYST-COATED MEMBRANE USING HALF ELECTRODE
EVALUATION SYSTEM ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 69
4.1 Introduction ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 69
4.2 Experimental ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 70
4.3 Results and Discussions ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 74
4.4 Summary ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 86
Chapter 5. EVALUATION OF GAS DIFFUSION ELECTRODE FOR HIGH TEMPERATURE
POLYMER ELECTROLYTE MEMBRANE FUEL CELL USING HALF ELECTRODE
EVALUATION SYSTEM ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 87
5.1 Introduction ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 87
5.2 Experimental ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 89
5.3 Results and Discussions ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 90
5.4 Summary ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 98
Chapter 6. Conclusion ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 99
REFERENCES ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 103
Acknowledgement ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 113
Curriculum Vitae ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 115
Publicatrions ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 116
Patents ․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․․ 11
Understanding Charge Density Wave Phase Transition in 1T-TaS2 via Machine Learning Force Field
No full textRecently, the charge density wave (CDW) phases and their properties in various condensed matter systems have been widely studied. In condensed matter, the formation of CDWs and periodic lattice distortions leads to changes in the electronic transport properties. Among these materials, 1T-type tantalum disulfide (1T-TaS2) is a layered material, and its CDW phases indicate a two-step phase transition depending on thickness and temperature. Experimental studies have shown that its physical properties depend on the stacking order of its layers, which affects the CDW phase transitions. However, due to its strong correlation between electronic structure and complex atomic geometry, understanding the CDW phase transition in 1T-TaS2 is challenging from a theoretical perspective. In this study, we investigated the tendency for structural change from molecular dynamics (MD) with the machine learning force field (MLFF), to simulate multiscale dynamics. We extracted a MLFF for a 1T-TaS2 monolayer based on Ab Initio Molecular Dynamics (AIMD) simulation training data on an Angstrom scale. Using this MLFF in MD simulations, we performed large-scale (∼< 100 nm^2) and long-time (∼< ns) simulations of temperature-dependent dynamics. Through these simulations, we discovered CDW phase transitions and domain wall formations at various temperatures and times, and analyzed their atomic composition. Our results not only theoretically predicted the temperature-dependent bulk CDW phase transition of 1T-TaS2, but also observed microscopic dynamics. This suggests that it will provide explanations consistent with previous experimental results. In future studies, our MLFF approach methodology could be applied to investigate bulk 1T-TaS2. Moreover, our findings may contribute to future studies that analyze light-induced hidden phases in 1T-TaS2 in detail, and could be extended to understand CDW phase transitions in other materials.MasterChapter 1. Introduction 1
1.1 Charge Density Wave (CDW) 1
1.1.1 Peierls Transition 1
1.1.2 Charge Density Waves: Materials and experiment 2
1.2 1T-TaS2 3
Chapter 2. Previous Research & Purpose 5
2.1 Previous Research 5
2.2 Purpose 6
Chapter 3. Methodology 8
3.1 Density Functional Theory (DFT) 8
3.1.1 Hatree-Fock (HF) Method 8
3.1.2 Kohn-Sham Equation 9
3.2 Molecular Dynamics (MD) 11
3.2.1 Ab-initio Molecular Dynamics (AIMD) 12
3.3 Machine Learning Force Field (MLFF) 13
3.3.1 Artificial Neural Network (NN) 14
3.3.2 MLFF with Symmetry functions 15
3.4 Computational details 16
Chapter 4. Result & Discussion 17
4.1 Model Evaluation 17
4.2 Atomic composition 18
4.2.1 No transition 18
4.2.2 CCDW-CCDW shift 19
4.2.3 Domain wall 22
4.2.4 NCCDW-ICCDW 22
4.3 Temperature-dependent Analysis 24
4.4 Diffraction Pattern 25
Chapter 5. Conclusion 28
Summary (한글 요약문) 29
Reference (참조문헌) 30
Acknowledgments (감사의 글) 34
Curriculum Vitae (약력) 3
Elimination of Micropollutants in Catalytic Ozonation using Aniline-Derived Metal-Carbon Composite
No full textThis study investigates the efficacy of aniline-derived metal-carbon catalysts (Me-N-C) in catalytic ozonation for the removal of persistent micropollutants from drinking water. Micropollutants, including pharmaceuticals and pesticides, pose significant environmental and public health challenges due to their persistence and resistance to conventional water treatment processes. Catalytic ozonation, leveraging enhanced hydroxyl radical (•OH) production, offers a promising solution to these limitations.
Five nitrogen-doped carbon-supported metal catalysts—manganese (Mn), nickel (Ni), copper (Cu), cobalt (Co), and iron (Fe)—were evaluated. Among these, Mn-N-C and Ni-N-C exhibited superior performance in promoting ozone decay, •OH radical generation, and micropollutant degradation. Notably, Mn-N-C achieved a highest removal of para-chlorobenzoic acid (pCBA) via combined •OH-driven reactions and adsorption mechanisms. Comparative analyses revealed that catalytic ozonation improved the removal efficiency of ozone-resistant micropollutants by 35.5% compared to conventional ozonation, achieving an average removal rate of 67.9%.
In addition to its high degradation efficiency, Mn-N-C demonstrated a 41.6% reduction in bromate formation, a key carcinogenic byproduct, compared to conventional ozonation. Furthermore, Mn-N-C enhanced dissolved organic carbon (DOC) removal by 45%, indicating its dual capability to mitigate disinfection byproduct formation while improving overall water quality. These results highlight the transformative potential of Mn-N-C catalysts in advancing catalytic ozonation as a sustainable and effective advanced oxidation process for drinking water treatment.MasterABSTRACT
Contents
List of Figures
List of Tables
List of Abbreviations
Chapter 1. Introduction 1
1.1 Introduction 1
1.2. Research Questions 5
Chapter 2. Literature Review 6
2.1. Ozonation and Micropollutant in drinking water 6
2.2. Catalytic Ozonation 8
2.2.1. Conventional Ozonation and Its Limitations 8
2.2.2. Catalytic Ozonation to overcome the limitations 9
2.2.3. Key Advantages of Hydroxyl Radicals (•OH) 9
2.2.4. Applications in Drinking Water Treatment 10
2.2.5. Improved Dissolved Organic Carbon (DOC) Removal 11
2.2.6. Control of Bromate Formation 11
2.3 Catalytic Ozonation Research Trends 12
2.4. Research Motivation 16
Chapter 3. Material and Methods 17
3.1. Materials 17
3.1.1 Chemicals 17
3.2 Experimental Methods 22
3.2.1 Catalytic Ozonation Performance Tests 22
3.2.2 Catalytic Ozonation for Micropollutant Elimination Tests 22
3.3 Analytical Methods 23
Chapter 4. Results and Discussions 25
4.1 Catalytic Ozonation Performance: Comparative Assessment of Metal Precursors in Me-N-C Catalysts 25
4.2 Effect of Metal Precursor Concentration on the Catalytic Ozonation Efficiency of Me-N-C Catalysts 30
4.3 Operational Performance Evaluation of Ni-N-C and Mn-N-C Catalysts 37
4.4 Comparative Elimination of Micropollutants: Ozonation vs. Catalytic Ozonation 43
Chapter 5. Conclusions 45
References 46
Curriculum Vitae 53
Acknowledgement 5