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Synthesis, Characterization, and Application of Microporous Layered Silicate AMH-3 with Selective Ion Exchange and Transport Properties : 선택적 이온 교환 및 투과 특성을 지닌 미세다공성 층상실리케이트 AMH-3의 합성, 특성 분석 및 응용에 관한 연구

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dc.contributor.advisor곽승엽-
dc.contributor.author김지훈-
dc.date.accessioned2018-05-28T16:17:29Z-
dc.date.available2018-05-28T16:17:29Z-
dc.date.issued2018-02-
dc.identifier.other000000150016-
dc.identifier.urihttps://hdl.handle.net/10371/140644-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 공과대학 재료공학부, 2018. 2. 곽승엽.-
dc.description.abstractMicroporous materials have been attracting great interest because of their ability to interact with atoms, ions and molecules not only at their surfaces, but throughout the bulk of the material. The utility of microporous materials is manifested in their microstructures (pore size, distribution, shape, volume), which allow molecules access to large internal surfaces and cavities that enhance catalytic activity and adsorptive capacity. Owing to this structures, microporous materials are widely used in various applications such as catalysts, adsorbents, molercular sieves.
AMH-3 is a layered microporous material constructed from silicate layers and interlayer spaces occupied by strontium cations, sodium cations, and water molecules. AMH-3 is the first layered silicate with micoroporosity through eight-membered ring (8-MR) apertures along the thickness of the silicate layer as well as in the plane of the layers. Because of this unique structure, AMH-3 has three-dimensional ordered microporosity and good acid, chemical and thermal stability like zeolite and provides the ability for intercalation, pillaring, and exfoliation like layered silicate.
Synthesis and characterization of AMH-3 and its synthesis mechanism study were conducted. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), 29Si magic angle spinning nuclear magnetic resonance (MAS NMR), fourier transform infrared (FT-IR), and Raman spectroscopy were used to characterize AMH-3. A reasonable model for the synthesis mechanism of AMH-3 is proposed on the basis of experiment results. In the synthesis process, strontium and titanium act as structuring agent and assembly agent, respectively.
The ion exchange behavior of AMH-3 and the removal of heavy metals present in aqueous solutions by AMH-3 are investigated for the first time. Pristine AMH-3 and ion-exchanged AMH-3 were characterized with ICP-AES, FE-SEM, 29Si CP MAS NMR and XRD. The studies on ion exchange behavior reveal that the sorption of ion by AMH-3 was found to be governed by ion exchange rather than surface adsorption, and no significant change occurred in the structure of the AMH-3 during the ion exchange. The removal of various heavy metal ions (Pb2+, Cu2+, Cd2+, and Zn2+) onto AMH-3 from aqueous solutions was conducted using a batch method. The effects of influential parameters, such as the initial metal ion concentration and contact time, on the sorption process were studied. The heavy metal ion sorption capacity and removal efficiency were mainly dependent on the difference between the effective pore size of the AMH-3 and the hydrated radius of the metal ion. The sorption isotherm data were well fitted by Langmuir (for Pb2+, Cu2+, and Zn2+) and Freundlich (for Cd2+) models. The sorption kinetics data were well fitted by a pseudo-second order kinetic model. Competitive sorption experiments revealed an order of metal ion affinity of Pb2+ > Cu2+ > Zn2+ > Cd2+. These findings indicate that AMH-3 is suitable for the efficient and selective removal of heavy metals from aqueous solutions.
In order to use as permselective barrier, the removal of the Na+ and Sr2+ cations located in the intralayer and interlayer spaces for activation of micropores and the delamination of an individual layer must be carried out. We successfully obtained delaminated AMH-3 by acid-hydrothermal treatment without the use of swelling agent. The post-treatment conditions have been optimized to find the best morphology for use as permselective barrier. The pristine AMH-3 and the delaminated AMH-3 were characterized with FE-SEM, N2 adsorption, ICP-AES, 29Si MAS NMR, FT-IR, Raman and XRD analyses. These results show that the delaminated AMH-3 has a more ordered pore structure than the pristine AMH-3 and that it retains framework crystallinity in the AMH-3 layers.
Utilizing AMH-3 with activated micropores, we sought to develop ion exchange membranes that have low vanadium crossover for use in vanadium redox flow batteries (VRBs). Nafion-based composite membrane containing delaminated AMH-3 (D-AMH-3) layer was prepared by solution casting and hot pressing. The membrane structure was analyzed by FE-SEM and EDS, revealing a sandwich-type structure that included double Nafion outer layers and a central D-AMH-3 layer. The Nafion/DAMH-3 membrane was employed as an ion exchange membrane for VRB application, and the vanadium permeability and single cell performance were evaluated. The Nafion/D-AMH-3membrane exhibited a lowerVO2+ permeability compared to Nafion, resulting in higher Coulombic efficiency and lower capacity loss per cycle. The results indicated that D-AMH-3 layer is potentially suitable as a permselective barrier for reducing vanadium crossover and improving cell performance.
Sulfonated poly(ether ether ketone) (SPEEK) is a potential polymer for replacing Nafion in VRBs. However, at a high degree of sulfonation, SPEEK displays high swelling, poor mechanical stability, and high vanadium crossover. In this study, to improve membrane performance, composite membranes of SPEEK and ultrasonicated D-AMH-3 (U-AMH-3) are prepared with various U-AMH-3 contents and investigated. The physicochemical and mechanical properties, vanadium permeability, and VRB single cell performance of these SPEEK/U-AMH-3 composite membranes are evaluated using various characterization techniques. Interactions between SPEEK and U-AMH-3, and the permselective property of U-AMH-3, result in the composite membranes exhibiting good mechanical properties and low vanadium crossover. Optimal composite membranes gave a VRB that produced a higher charge–discharge capacity, higher cell efficiency, and better capacity retention than that using Nafion. These results indicate that SPEEK-based composite membranes with improved membrane performance, lower vanadium crossover, and good single cell performance were successfully prepared by incorporating U-AMH-3.
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dc.description.tableofcontentsCHAPTER I. INTRODUCTION 1
I-1. Microporous materials 1
I-1-1. Aluminosilicates (zeolites) 2
I-1-2. Titanosilicates 8
I-2. Layered materials 11
I-2-1. Layered silicates 12
I-2-2. Layered zeolitic materials 15
I-3. AMH-3 18
I-4. Research Objectives 25

CHAPTER II. SYNTHESIS OF LAYERED SILICATE AMH-3 AND ITS SYNTHESIS MECHANISM STUDY 29
II-1. Introduction 29
II-2. Experimental Section 34
II-2-1. Materials 34
II-2-2. Synthesis of AMH-3 34
II-2-3. Characterization 35
II-3. Results and Discussion 36
II-3-1. Characterization of AMH-3 36
II-3-2. Synthesis mechanism study 44
II-4. Conclusion 54

CHAPTER III. ION EXCHANGE BEHAVIOR OF LAYERED SILICATE AMH-3 AND ITS APPLICATION AS SORBENT FOR HEAVY METAL IONS 55
III-1. Introduction 55
III-2. Experimental Section 59
III-2-1. Materials 59
III-2-2. Ion exchange study 59
III-2-3. Removal of heavy metal ions 61
III-2-4. Characterization 63
II-3. Results and Discussion 65
III-3-1. Ion exchange behavior 65
III-3-2. Characterization of ion exchanged AMH-3 76
III-3-3. Removal of heavy metal ions 81
III-4. Conclusion 95

CHAPTER IV. EFFICIENT REMOVAL OF CATIONS FROM LAYERED SILICATE AMH-3 FOR ACTIVATION OF MICROPORES 96
IV-1. Introduction 96
IV-2. Experimental Section 99
IV-2-1. Materials 99
IV-2-2. Removal of cations within AMH-3 99
IV-2-3. Characterization 100
IV-3. Results and Discussion 101
IV-3-1. Morphology and quantitative analysis 101
IV-3-2. Structural analysis 107
IV-4. Conclusion 118

CHAPTER V. NAFION/LAYERED SILICATE AMH-3 COMPOSITE MEMBRANE WITH SANDWICH-TYPE STRUCTURE FOR VANADIUM REDOX FLOW BATTERIES 119
V-1. Introduction 119
V-2. Experimental Section 125
V-2-1. Materials 125
V-2-2. Membrane preparation 125
V-2-3. Characterization 126
V-2-4. VRB single cell test 128
V-3. Results and Discussion 130
V-3-1. Membrane morphology 130
V-3-2. Physicochemical properties 132
V-3-3. Vanadium permeability 133
V-3-4. VRB single cell performance 138
V-4. Conclusion 149

Chapter VI. SULFONATED POLY(ETHER ETHER KETONE) COMPOSITE MEMBRANES WITH LAYERED SILICATE AMH-3 FOR IMPROVED PERFORMANCE IN VANADIUM REDOX FLOW BATTERIES 150
VI-1. Introduction 150
VI-2. Experimental Section 154
VI-2-1. Materials 154
VI-2-2. Preparation of U-AMH-3 154
VI-2-3. Membrane preparation 155
VI-2-4. Characterization 156
VI-2-5. VRB single cell test 160
VI-3. Results and Discussion 161
VI-3-1. Characterization of U-AMH-3 161
VI-3-2. Membrane morphology 165
VI-3-3. Physicochemical properties 167
VI-3-4. Proton conductivity and vanadium permeability 172
VI-3-5. VRB single cell performance 180
VI-4. Conclusion 190

REFERENCES AND NOTES 191
KOREAN ABSTRACT 204
LIST OF PAPERS AND PATENTS 211
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dc.formatapplication/pdf-
dc.format.extent11190327 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectMicroporous-
dc.subjectLayered silicate-
dc.subjectAMH-3-
dc.subjectIon exchange-
dc.subjectSorbent-
dc.subjectHeavy metal ion-
dc.subjectIon transport-
dc.subjectVanadium redox flow battery-
dc.subject.ddc620.1-
dc.titleSynthesis, Characterization, and Application of Microporous Layered Silicate AMH-3 with Selective Ion Exchange and Transport Properties-
dc.title.alternative선택적 이온 교환 및 투과 특성을 지닌 미세다공성 층상실리케이트 AMH-3의 합성, 특성 분석 및 응용에 관한 연구-
dc.typeThesis-
dc.description.degreeDoctor-
dc.contributor.affiliation공과대학 재료공학부-
dc.date.awarded2018-02-
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