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Development of Bismuth/Graphene Nanocomposite-Modified Electrodes and Their Application for Electrochemical Detection of Trace Heavy Metal Ions
비스무스/그래핀 나노복합체로 개질된 전극 개발 및 미량 중금속 이온의 전기화학적 검출 응용

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dc.contributor.advisor박원철-
dc.contributor.author이소희-
dc.date.accessioned2017-07-14T01:49:04Z-
dc.date.available2017-07-14T01:49:04Z-
dc.date.issued2017-02-
dc.identifier.other000000140756-
dc.identifier.urihttps://hdl.handle.net/10371/122370-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 융합과학부, 2017. 2. 박원철.-
dc.description.abstractHeavy metals are considered one of the main sources of environmental pollution. Their main source is industrial activity, which directly or indirectly discharge the heavy metal species into the environment. Certain heavy metals (e.g., mercury, cadmium, chromium, and lead) are highly toxic and affect several human organs, even at trace levels. For example, mercury and lead are known to cause damage to the nervous system, cadmium causes kidney and bone disease, and excessive absorption of zinc affects multiple aspects of the immune system. Heavy metal pollution is of great concern for global sustainability. It is therefore essential to monitor heavy metals in the environment, drinking water, food, and biological fluids. Traditional analytical methods include atomic absorption spectroscopy (AAS), inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled atomic emission spectrometry (ICP-AES). Although these techniques are highly sensitive and selective, they require laborious pre-treatment processes, expensive instruments, and professional personnel. In contrast, analytical electrochemical stripping techniques have attracted great interest in the detection of heavy metals. Owing to properties including short analytical time, low cost, and high sensitivity, electrochemical detection methods have been widely recognized as powerful techniques for the detection of heavy metals. In particular, anodic stripping voltammetry (ASV), a technique that consists of deposition and stripping steps, is used very frequently. Mercury electrodes have proven to be valuable tools for this technique. However, considering their toxicity and the difficulty involved in the handling of mercury, these electrodes have recently been replaced by mercury-free electrodes. Several elements have been tested for their capacity to replace mercury (e.g., bismuth, gold, silver, antimony, and carbon). In recent years, bismuth electrodes have been attracting increasing attention in ASV analysis. The remarkable stripping performance of bismuth electrodes is attributed to the ability of bismuth to form fused alloys with heavy metals. These alloys are analogous to the amalgams formed by mercury. Additionally, because of their fast electron transfer rate, unique structural characteristics, and high surface area, carbon-based nanomaterials are employed extensively as sensing materials to detect heavy metals.
This dissertation aims at presenting the fabrication of bismuth-based nanocomposites that can be employed in the development of electrochemical sensors for the detection of heavy metals.
Firstly, chemically activated reduced graphene (AG) was used with Nafion as a sensing material for the first time. This material was placed on a glassy carbon electrode (GCE, modified by in-situ-deposited bismuth) to fabricate an electrochemical platform for the simultaneous and individual determination of three heavy metals in solution. Next, the graphene was prepared by electrochemical deposition directly onto a GCE surface. The bismuth film was then deposited in situ on the surface of the electrochemical sensor electrode that was used for sensitive determination of trace heavy metals. Finally, an iron oxide/graphene nanocomposite was directly produced by heat treatment of a mixture of iron oleate and graphene. The GCE was modified with the as-prepared nanocomposite, and employed as an electrochemical sensing platform for sensitive analysis of heavy metal ions. The generated iron oxide nanoparticles were homogeneously embedded in the graphene layers. These act as mutual spacers in the nanocomposite, preventing restacking of the graphene, and enhancing the detection sensitivity towards heavy metals.
These bismuth-based nanocomposites enable the electrochemical sensing of heavy metals with graphene- or nanoparticle-modified electrodes. The results suggest that these nanocomposites can improve the sensitivity and stability of the system.
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dc.description.tableofcontentsChapter 1. Introduction: Bismuth/Graphene Nanocomposite-Modified Electrodes for Detection of Trace Heavy Metal Ions and Dissertation Overview 1
1.1 Introduction 1
1.2 Electrochemical Sensors 9
1.2.1 Electrochemical Stripping Techniques 11
1.2.2 Voltammetric Stripping 13
1.2.3 Electrode Materials for Stripping Voltammetry 19
1.2.3.1 Mercury Electrodes 19
1.2.3.2 Gold and Silver Electrodes 22
1.2.3.3 Carbon-based Electrodes 23
1.2.3.4 Bismuth Electrodes 29
1.3 Preparation of Bismuth-based Electrochemical Electrodes 31
1.3.1 Design of Bismuth Electrodes 31
1.3.2 Synthesis of Bismuth Nanoparticles 32
1.3.2.1 Chemical Methods 33
1.3.2.2 Physical Methods 34
1.3.2.3 Electrochemical Methods 38
1.3.3 Bismuth-based Modifications and Nanocomposite for Detection of Heavy Metal Ions 48
1.3.3.1 Metal Nanoparticles 48
1.3.3.2 Carbon Nanotubes 50
1.3.3.3 Other Nanomaterials 54
1.4 Preparation of Bismuth/Graphene Nanocomposite Electrodes 55
1.4.1 Graphene 55
1.5 Dissertation Overview 60
References 64
Chapter 2. Synthesis of Activated Graphene/Bismuth Nanocomposite for Electrochemical Detection of Trace Heavy Metal Ions 71
2.1 Introduction 71
2.2 Experimental Section 75
2.2.1 Chemicals 75
2.2.2 Characterization Methods 75
2.2.3 Apparatus 76
2.2.4 Preparation of the Activated Graphene and Reduced Graphene Oxide 76
2.2.5 Preparation of the AG/Nafion (NA) Nanocomposite Modified Electrode 77
2.2.6 Fabrication of Bismuth (Bi)-coated the AG/NA Nanocomposite Modified Electrode 78
2.2.7 Procedure for Differential Pulse Anodic Stripping Voltammetry Analysis 78
2.3 Results and Discussion 79
2.3.1 Characterization of the AG and AG/NA/Bi composite 79
2.3.2 Electrochemical Characterization 87
2.3.3 Effect of Experimental Variables 89
2.3.4 Analytical Performance 98
2.3.5 Application to Real Environments 101
2.4 Conclusion 103
References 104
Chapter 3. Development of an Electrochemically Reduced Graphene Oxide/Bismuth Modified Electrode for Stripping Analysis of Heavy Metal Ions 107
3.1 Introduction 107
3.2 Experimental Section 111
3.2.1 Chemicals 111
3.2.2 Characterization Methods 112
3.2.3 Apparatus 112
3.2.4 Preparation of Graphene Oxide 113
3.2.5 Preparation of Electrochemically Reduced Graphene Oxide (EG) Modified Electrode 114
3.2.6 Preparation of EG/Bismuth (Bi) Nanocomposite Modified Electrode 115
3.2.7 Procedure for Differential Pulse Anodic Stripping Voltammetry Analysis 115
3.3 Results and Discussion 122
3.3.1 Characterization of EG/Bi Composite 122
3.3.2 Electrochemical Characterization 122
3.3.3 Optimization of Experimental Parameters 129
3.3.4 Analytical Performance 131
3.3.5 Application to Real Environments 133
3.3.6 Interference Study 134
3.4 Conclusion 135
References 137
Chapter 4. Iron oxide/Graphene/Bismuth Nanocomposite for Electrochemical Detection of Heavy Metal Ions 140
4.1 Introduction 140
4.2 Experimental Section 144
4.2.1 Chemicals 144
4.2.2 Characterization Methods 144
4.2.3 Apparatus 145
4.2.4 Preparation of Reduced Graphene Oxide (RGO) 145
4.2.5 Preparation of Iron-oxide Nanoparticles (F2O3)/Graphene (G) Nanocomposite 146
4.2.6 Fabrication of Bismuth-coated Fe2O3/G Nanocomposite Modified Electrode 149
4.2.7 Procedure for Differential Pulse Anodic Stripping Voltammetry Analysis 149
4.3 Results and Discussion 154
4.3.1 Characterization of Fe2O3/G Nanocomposite 154
4.3.2 Electrochemical Characterization 155
4.3.3 Analytical Performance 157
4.3.4 Optimization of Experimental Parameters 164
4.3.5 Application to Real Environments 172
4.3.6 Reproducibility of the Fe2O3/G/Bi Modified Electrode 173
4.3.7 Interference Study 173
4.4 Conclusion 174
References 178
Chapter 5. Conclusion 184
Bibliography 190
국 문 초 록 195
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dc.formatapplication/pdf-
dc.format.extent3992371 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectBismuth-
dc.subjectnanocomposite-
dc.subjectHeavy metal detection-
dc.subjectGraphene-
dc.subjectAnodic stripping voltammetry-
dc.subjectElectrochemical sensor-
dc.subjectModified electrode-
dc.subject.ddc620-
dc.titleDevelopment of Bismuth/Graphene Nanocomposite-Modified Electrodes and Their Application for Electrochemical Detection of Trace Heavy Metal Ions-
dc.title.alternative비스무스/그래핀 나노복합체로 개질된 전극 개발 및 미량 중금속 이온의 전기화학적 검출 응용-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pagesxii, 198-
dc.contributor.affiliation융합과학기술대학원 융합과학부-
dc.date.awarded2017-02-
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Graduate School of Convergence Science and Technology (융합과학기술대학원)Dept. of Transdisciplinary Studies(융합과학부)Theses (Ph.D. / Sc.D._융합과학부)
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