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Preparation and Characterization of Graphene Oxide Modified Membranes for Water Treatment
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | 이정학 | - |
| dc.contributor.author | 이재우 | - |
| dc.date.accessioned | 2017-07-13T08:40:19Z | - |
| dc.date.available | 2017-07-13T08:40:19Z | - |
| dc.date.issued | 2015-02 | - |
| dc.identifier.other | 000000026091 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/119741 | - |
| dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 화학생물공학부, 2015. 2. 이정학. | - |
| dc.description.abstract | Today a third of the global population lives in water shortage country, one of the pressing needs of people throughout the world is adequate supply of drinking water. To satisfy the demand for an enormous amount of water required by expanding global population, there have been much erudite discussions and practical attempts covering a wide scope including wastewater reuse as well as desalination. Among several technologies, in particular, membrane bioreactor (MBR) and reverse osmosis (RO) process have attracted much attention in the field of wastewater treatment and desalination, respectively, due to various strengths such as high quality of treated water and a small footprint. However, MBR have membrane fouling which is the major obstacle in maximizing their efficiency leading to short membrane lifetime and high operating costs. Also, for the RO process, low energy efficiency still remains unanswered as a serious challenge in RO process over the past few decades. In this study, it is demonstrated that the application of graphene oxide (GO) to membrane fabrication can be a novel strategy to overcome the aforementioned residual problems with each membrane process. In detail, GO was applied to fabrication of polysulfone (PSf) ultrafiltration (UF) membrane for the improvement of hydrophilicity and electrostatic repulsion characteristics, and the anti-biofouling capability of GO nanocomposite membrane was proved to be effective in MBR. Furthermore, addition of GO enhanced mechanical strength of GO nanocomposite membrane due to its high modulus and aspect ratio, which enabled the GO nanocomposite UF membrane to have mechanical strength comparable to existing support layer for commercial RO membrane and highly porous structure simultaneously. It is worth noting that RO membrane consisting of the PSf/GO nanocomposite support layer outperformed others including commercial membranes as well as the previously reported membranes in open literature. Also noteworthy is increasing the porosity of support layer could lead to improving the efficiency of RO membrane. To clarify the reason why porous structure of support layer induces higher water permeability of RO membrane, a non-intrusive experimental method was devised for representing the characteristics of the support layer as related to water flux. | - |
| dc.description.tableofcontents | Table of Contents
Abstract i List of Figures vii List of Tables xvi I. Introduction 1 I.1. Backgrounds 2 I.2. Objectives 4 II. Literature Review 7 II.1. Phase inversion in polymer system 8 II.1.1. Introduction 8 II.1.2. Nonsolvent induced phase separation method 12 II.1.3. Membrane structures prepared by nonsolvent induced phase separation: finger- and sponge-like structure 17 II.1.4. Factors affecting pore structure of membrane prepared by nonsolvent induced phase separation 21 II.2. Interfacial polymerization 28 II.2.1. History of reverse osmosis membrane 28 II.2.2. Fabrication of thin-film composite reverse osmosis membrane using interfacial polymerization 35 II.2.3. Recent trend of reverse osmosis membrane 39 II.3. Graphene oxide 48 II.3.1. Introduction 48 II.3.2. Synthesis of graphene oxide platelets 54 II.3.3. Preparation of graphene-based polymer nanocomposite: Non-covalent dispersion methods 58 II.3.4. Mechanical properties of graphene-based polymer nanocomposite 59 III. Graphene Oxide Nanoplatelets Composite Membrane with Hydrophilic and Antifouling Properties for Wastewater Treatment 61 III.1. Introduction 62 III.2. Experimental section 65 III.2.1. Materials 65 III.2.2. Preparation of graphene oxide and reduced graphene oxide solution. 66 III.2.3. Preparation of the membranes 68 III.2.4. Characterization 69 III.2.5. Pure water flux measurement 72 III.2.6. Microorganism attachment test 73 III.2.7. Membrane bioreactor operation 74 III.3. Results and discussion 78 III.3.1. Conformation of graphene oxide in polysulfone/graphene oxide membrane 78 III.3.2. Anti-biofouling activity of polysulfone/graphene oxide membrane 82 III.3.3. Hydrophilicity of polysulfone/graphene oxide membrane 88 III.3.4. Membrane pore size distribution and pore cross-sectional structure 91 III.3.5. Mechanical strength of polysulfone/graphene oxide membrane 99 III.3.6. Membrane bioreactor operation 101 III.4. Conclusions 104 IV. Impact of Support Layer on Thin-Film Composite Reverse Osmosis Membrane Performance 105 IV.1. Introduction 106 IV.2. Experimental section 108 IV.2.1. Fabrication of polysulfone porous support layer 108 IV.2.2. Fabrication of polyamide active layer by interfacial polymerization 109 IV.2.3. Characterization 110 IV.2.4. Reverse osmosis test 113 IV.2.5. Forward osmosis test 115 IV.3. Results and discussion 116 IV.3.1. Control of support layer structure using pore formation mechanism in phase inversion 116 IV.3.2. Correlation between mean surface pore size of support layer and active layer thickness of reverse osmosis membrane 119 IV.3.3. Correlation between active layer characteristics of reverse osmosis membrane and water flux 123 IV.3.4. Pressure drop and water transport behaviour in support layer during reverse osmosis operation 127 IV.3.5. Correlation between the characteristics of support layer and water flux of reverse osmosis membrane. 134 IV.3.6. Various characteristics of a thin-film composite membrane on water flux of reverse osmosis membrane 138 IV.4. Conclusions 142 V. Size-Controlled Graphene Oxide Enabling Thin-Film Composite Reverse Osmosis Membrane to Have Highly Porous Support Layer for High Performance 143 V.1. Introduction 144 V.2. Experimental section 148 V.2.1. Preparation of size-controlled graphene oxide platelets 148 V.2.2. Fabrication of size-controlled graphene oxide platelets composite reverse osmosis membrane 150 V.2.3. Characterization 151 V.2.4. Reverse osmosis test 153 V.3. Results and discussion 154 V.3.1. Size control of graphene oxide platelets by applying different mechanical energy input per volume 154 V.3.2. Structural integrities of graphene oxide platelets according to different sizes 156 V.3.3. Mechanical properties of polysulfone/graphene oxide nanocomposite membranes 158 V.3.4. Effective characteristics of graphene oxide platelets to improve mechanical properties of polymer nanocomposites 160 V.3.5. Influence of graphene oxide addition on structural characteristics of active and support layers 166 V.3.6. Performance of reverse membrane made of polysulfone/graphene oxide nanocomposites support layer 175 V.4. Conclusions 178 VI. Conclusions 180 Nomenclature 183 Greek letters 187 References 188 국문 초록 213 | - |
| dc.format | application/pdf | - |
| dc.format.extent | 9898445 bytes | - |
| dc.format.medium | application/pdf | - |
| dc.language.iso | en | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject | Ultrafiltration (UF) membrane | - |
| dc.subject | Thin-film composite (TFC) reverse osmosis (RO) membrane | - |
| dc.subject | Graphene oxide (GO) | - |
| dc.subject | Anti-biofouling property | - |
| dc.subject | Mechanical property | - |
| dc.subject | Support layer impact | - |
| dc.subject.ddc | 660 | - |
| dc.title | Preparation and Characterization of Graphene Oxide Modified Membranes for Water Treatment | - |
| dc.type | Thesis | - |
| dc.description.degree | Doctor | - |
| dc.citation.pages | xvii, 214 | - |
| dc.contributor.affiliation | 공과대학 화학생물공학부 | - |
| dc.date.awarded | 2015-02 | - |
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