Thermal stability-enhanced tetraethylenepentamine/silica adsorbents for high performance CO2 capture
Thermal stability-enhanced tetraethylenepentamine/silica adsorbents for high performance CO2 capture
- 주제(키워드) CO2 capture , Tetraethylenepentamine , Epoxide functionalization , Thermal stability , Adsorption kinetics
- 발행기관 고려대학교 대학원
- 지도교수 이정현
- 발행년도 2018
- 학위수여년월 2018. 8
- 유형 Text
- 학위구분 석사
- 학과 대학원 화공생명공학과
- 원문페이지 56 p
- 실제URI http://www.dcollection.net/handler/korea/000000081557
- UCI I804:11009-000000081557
- DOI 10.23186/korea.000000081557.11009.0000814
- 본문언어 영어
- 제출원본 000045953829
초록/요약
Continuous increases in CO2 emissions caused by anthropogenic activities have been deemed as the main cause for global warming, illuminating the need to synthesize the advanced, efficient CO2 capturing material. Tetraethylenepentamine (TEPA), mainly consisting of primary and secondary amines, exhibits a high CO2 sorption capacity, suggesting its potential application for the post-combustion CO2 capture. However, its poor thermal stability hampers practical utilization in the temperature swing adsorption process for CO2 removal. Here, a facile functionalization of TEPA with 1,2-epoxybutane (EB) has been found to substantially enhance its thermal stability due to the increase in its molecular weight as well as the formation of hydrogen bonding between amine moieties and hydroxyl groups. Our careful analysis on the liquid-phase 13C-NMR results reflected that the relative concentration of primary amines decreased while that of tertiary amines increased with increasing degree of functionalization. Although the increase in tertiary amine portion induced by EB functionalization reduced CO2 sorption capacity, the 0.64EB-functionalized TEPA/SiO2 showed an excellent long-term stability over the 10 consecutive cycles of adsorption/desorption processes with a CO2 swing capacity of 2.0 mmol CO2 g-1 under dry CO2/N2 (15/85 mol/mol) feed at ambient condition. Also, the increase in the amount of EB used to modify TEPA geometry contributed to improve CO2 adsorption kinetics due to the enlarged d-spacing between the main chains of neighboring TEPA molecules which was verified by using X-ray diffraction and the first principles calculations. Our simple approach that serves TEPA to enhance the thermal stability as well as the CO2 adsorption kinetics for solid CO2 adsorbents provides significant interest in its potential application as high performance CO2 capturing material.
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ABSTRACT ⅰ
CONTENTS ⅲ
LIST OF FIGURES ⅴ
LIST OF TABLES ⅷ
CHAPTER 1. INTRODUCTION 1
1.1 Introduction 1
1.2 Introduction to CO2 Capture 2
CHAPTER 2. EXPERIMENTS 7
2.1 Materials 7
2.1.1 Synthesis of Spray-dried Silica 7
2.1.2 Preparation of Adsorbents 9
2.2 Experimental Methods 11
2.2.1 CO2 Adsorption/Desorption Experiments 11
2.3 Supplementary Characterizations 11
2.3.1 Element Analyzer (EA) 11
2.3.2 Scanning Electron Microscopy (SEM) 11
2.3.3 Nuclear Magnetic Resonance (NMR) 11
2.3.4 Brunauer-Emmett-Teller (BET) 12
2.3.5 Thermogravimetric Analysis (TGA) 12
2.3.6 Heat of Adsorption 12
2.3.7 X-ray diffraction (XRD) 12
2.3.8 Fourier Transform Infrared Spectroscopy (FT-IR) 12
2.4 Computational Methods 13
CHAPTER 3. RESULTS AND DISCUSSIONS 14
3.1 Epoxide-Functionalized TEPA 14
3.2 Characterization of TEPA- or EB-TEPA/SiO2 Adsorbents 23
3.3 Long-Term CO2 Swing Capacity of TEPA- or EB-TEPA/SiO2 Adsorbents 29
3.4 Adsorption Kinetics of TEPA- or EB-TEPA/SiO2 Adsorbents 33
CHAPTER 4. CONCLUSIONS 40
REFERENCES 41
