由於經濟發展、人口增加與氣候變遷等因素，造成水資源日漸匱乏，海水淡化技術成為近年來各國開發的重點技術。電容去離子技術(Capacitive Deionization, CDI)是一種利用電吸附程序去除水中離子的電化學水處裡技術。CDI技術具有操作簡便、無二次污染及低耗能等優勢。電極材料是影響CDI性能的最重要因素之一，本研究著重於開發奈米鐵/石墨烯複合材料及利用奈米鐵/石墨烯複合材料於CDI系統，以去除水中的鹽類與重金屬。
本研究所使用的電極材料為多孔石墨烯，多孔石墨烯是以混合強酸(HNO3:H2SO4=2:1)處理過的石墨烯，由於石墨烯略為疏水，較不利於水處理程序，因此利用混合強酸改質，改善石墨烯之親疏水性。
本研究想提升多孔石墨烯之表面特性及電化學特性，因此添加奈米鐵金屬，使用微波合成及水熱合成兩種方法改質多孔石墨烯，這兩種方法皆可提升電極之比表面積，將合成之奈米鐵/多孔石墨烯應用於CDI系統，進行NaCl溶液之電吸附，水熱合成之奈米鐵/多孔石墨烯複合材料表現較佳，電吸附量為2.86 mg NaCl/g electrode，而微波合成之複合材料之電吸附量為2.29 mg NaCl/g electrode，因此推斷水熱合成之奈米鐵/多孔石墨烯複合材料更適合應用於CDI技術上。
以水熱合成之奈米鐵/多孔石墨烯複合材料應用於CDI系統，去除水中重金屬鉛，電吸附量為4.2 mg PbCl2/g electrode；去除水中重金屬銅，電吸附量為3.88 mg CuCl2/g electrode。

Due to economic development, population growth and climate change, water resources become shortage. Therefore, desalination technology has become a key technology developed by many countries in recent years. Capacitive Deionization (CDI) is a technique for removing ions from water by electrosorption. There are several advantages of CDI system, including no secondary pollution, easy to install and energy efficiency. The electrode material is one of the most important factors to affect the performance of CDI. Therefore, in this study we focus on developing nano Fe/graphene composites to remove salt and heavy metals from water.
The electrode material used in this study is holey graphene. The holey graphene is graphene treated with mixed strong acid (HNO3:H2SO4=2:1). Due to slightly hydrophobic property of graphene, which is not desirable for water treatment process, we employ the mixed strong acid to improve the hydrophilicity of graphene.
In this study, we want to improve the surface characteristics and electrochemical properties of porous graphene. With addition of nano iron, microwave synthesis or hydrothermal synthesis is used to modify holey graphene. Both methods can increase the specific surface area of the electrode. These two Fe/HrGO composites were applied to the CDI system for electrosorption studies of NaCl solution. The Fe/HrGO composite synthesized by hydrothermal synthesis has better CDI performance than that of microwave synthesis, which has higher electrosorption capacity of 2.86 mg NaCl/g electrode. While the microwave synthesized Fe/HrGO composite can only electrosorb 2.29 mg NaCl/g electrode. Therefore, it is concluded that hydrothermally synthesized Fe/HrGO composites are more suitable for CDI technology.
Hydrothermally synthesized Fe/HrGO composites were applied to CDI system for removal of heavy metal (Pb or Cu). In the case of removal Pb, the electrosorption capacity is 4.2 mg PbCl2/g electrode. In the case of removal Cu, the electrosorption capacity is 3.88 mg CuCl2/g electrode.

目錄
目錄	I
第一章	研究緣起與目的	1
1.1	研究緣起	1
1.2	研究目的	2
第二章	文獻回顧	3
2.1	海水淡化技術	3
2.1.1	多效蒸發法(Multi-effect Distillation, MED)	4
2.1.2	多級閃化法(Multi-Stage Flash, MSF)	5
2.1.1	逆滲透(Reverse Osmosis, RO)	6
2.1.2	電透析(Electrodialysis, ED)	7
2.2	電容去離子技術(Capacitive Deionization, CDI)	8
2.2.1	電容去離子技術發展之簡介	9
2.2.2	電容去離子技術之原理	11
2.3	電容去離子之電極種類	12
2.3.1	活性碳(Activated Carbons)	13
2.3.2	碳氣凝膠(Carbon Aerogel)	14
2.3.3	奈米碳管(Carbon Nanotubes)	15
2.3.4	石墨烯(Graphene)	16
2.4	法拉第電流之過渡金屬氧化物	18
2.5	去除水中重金屬	19
第三章	實驗設備與方法	21
3.1	實驗架構	21
3.2	實驗藥品與設備	23
3.2.1	實驗藥品	23
3.2.2	實驗設備	24
3.3	電極材料之製作	25
3.3.1	氧化石墨烯(GO)之製備	25
3.3.2	多孔氧化石墨烯(HGO)之製備	27
3.3.3	多孔石墨烯(HrGO)之製備	28
3.3.4	微波Fe/HrGO之製備	29
3.3.5	水熱Fe/HrGO之製備	30
3.4	電極之製作	31
3.4.1	電化學分析之電極	31
3.4.2	CDI反應器之電極	31
3.5	儀器分析方法	32
3.5.1	X-ray繞射儀 (XRD)	32
3.5.2	掃描式電子顯微鏡(SEM)	32
3.5.3	穿透式電子顯微鏡(TEM)	32
3.5.4	BET孔徑與表面積分析	33
3.5.5	Contact angle 接觸角試驗	33
3.5.6	循環伏安法(Cyclic Voltammetry, CV)	34
3.5.7	計時電位法(Chronopotentiometry)	34
3.5.8	計時電流法(Chronoamperometry)	34
3.5.9	電化學阻抗分析(Electrochemical Impedance Spectroscopy)	……………………………………………………………..35
3.5.10	電容去離子實驗(CDI System)	35
3.5.11	微波消化系統ETHOS EASY	37
3.5.12	感應耦合電漿發射光譜儀ICP-OES	37
第四章	結果與討論	38
4.1	微波合成Fe/HrGO複合材料應用於CDI	38
4.1.1	微波合成Fe/HrGO複合材料表面特性分析	38
4.1.2	微波合成Fe/HrGO複合材料電化學分析	47
4.1.3	微波合成Fe/HrGO複合材料應用於電容去離子	54
4.2	水熱合成Fe/HrGO複合材料應用於CDI	56
4.2.1	水熱合成Fe/HrGO複合材料表面特性分析	56
4.2.2	水熱合成Fe/HrGO複合材料電化學分析	63
4.2.3	水熱合成Fe/HrGO複合材料應用於電容去離子	70
4.3	水熱合成Fe/HrGO複合材料應用於CDI去除水中重金屬	72
4.3.1	去除水中重金屬鉛(Pb)	72
4.3.2	去除水中重金屬銅(Cu)	74
第五章	結論及建議	76
Reference	78

 
List of Figure
Figure 2.1.1.1 Global desalination technologies share by capacity.	3
Figure 2.1.1.1 Schematic diagram of the MED plant at PSA.	4
Figure 2.1.2.1 Schematic diagram of the evaporating section of an MSF desalination plant. The demister is installed to remove the numberless tiny liquid droplet occurred in the evaporation process and to conserve the quality of a produced freshwater.(Choi, 2016)	5
Figure 2.1.1.1Mechanism of reverse osmosis (Gasmi, Belgaieb, & Hajji, 2010)	6
Figure 2.1.2.1 The schematic set up of ED stack (Khan et al., 2017)	7
Figure 2.2.1.1 Timeline of scientific developments of CDI, indicating milestones	10
Figure 2.2.2.1 Purification (a) and regeneration (b) processes in CDI.	11
Figure 2.3.3.1 Structural models of a SWCNT (left) and an MWCNT (right).	15
Figure 2.3.4.1 TEM image of GO nanosheet showing a clear and transparent	17
Figure 3.1 Schematic experimental structure for CDI system.	22
Figure 3.3.1.1 Graphene oxide (GO) preparation procedure.	26
Figure 3.3.2.1 Holey Graphene Oxide (HGO) preparation procedure.	27
Figure 3.3.3.1 Holey Reduced Graphene Oxide (HrGO) preparation procedure.	28
Figure 3.3.4.1 Fe/Holey Reduced Graphene Oxide (Fe/HrGO) preparation procedure via microwave syntheses.	29
Figure 3.3.5.1 Fe/Holey Reduced Graphene Oxide (Fe/HrGO) preparation procedure	30
Figure 3.5.10.1 Schematic diagram of the CDI setup.	36
Figure 4.1.1.1 XRD patterns of (a) GO, (b) HrGO, and (c) Fe/HrGO (Microwave	39
Figure 4.1.1.2 FE-SEM images of FE-SEM images of the (a, b) HrGO	42
Figure 4.1.1.3 FE-SEM images of the (a, b, c, d, e, f) Fe/HrGO (Microwave	42
Figure 4.1.1.4 (a, b) FE-SEM image with EDS on one Fe nanoparticle and (c) an	43
Figure 4.1.1.5 TEM images of the Fe/HrGO HrGO (Microwave synthesis).	44
Figure 4.1.1.6 TEM images of the Fe/HrGO (Microwave synthesis).	44
Figure 4.1.1.7 TEM image with EDS on one Fe nanoparticle.	45
Figure 4.1.1.8 Contact angle images of the (a, b) HrGO, (c, d) Fe/HrGO	46
Figure 4.1.2.1 CV patterns of the Fe/ HrGO (Microwave synthesis).	48
Figure 4.1.2.2 Mass normalized specific capacitance of Fe/HrGO (Microwave	48
Figure 4.1.2.3 Charge-discharge curves of Fe/HrGO (Microwave synthesis) under	51
Figure 4.1.2.4 The current-time response obtained at applied cyclic potential on	52
Figure 4.1.2.5 The electrochemical impedance spectra (EIS) measured at frequency range of 100 kHz to 0.01 Hz for HrGO and Fe/HrGO (Microwave synthesis) composites electrode, respectively and the equivalent circuit for fitting EIS spectrum.(Yang et al., 2017)	53
Figure 4.1.3.1 Electrosorption/desorption profiles of the Fe/HrGO (microwave	55
Figure 4.2.1.1 XRD patterns of (a) GO, (b) HrGO, and (c) Fe/HrGO (H-thermal)	57
Figure 4.2.1.2 FE-SEM images of the (a, b, c, d ) HrGO, (e, f, g, h) Fe/HrGO	59
Figure 4.2.1.3 (a, b) FE-SEM image with EDS on one Fe nanoparticle. (c)	60
Figure 4.2.1.4 TEM images of the (a, b) HrGO, (c, d) Fe/HrGO.	61
Figure 4.2.1.5 TEM image with EDS on one Fe nanoparticle.	61
Figure 4.2.1.6 Contact angle images of the (a, b) HrGO, (c, d) Fe/HrGO.	62
Figure 4.2.2.1 CV patterns of the Fe/ HrGO at various scan rates in 1M NaCl solution.	64
Figure 4.2.2.2 Mass normalized specific capacitance of Fe/HrGO composites withrespect to the scan rates.	64
Figure 4.2.2.3 Charge-discharge curves of Fe/HrGO under different current densities.	67
Figure 4.2.2.4 The current-time response obtained at applied cyclic potential on	68
Figure 4.2.2.5 The electrochemical impedance spectra (EIS) measured at frequency	69
Figure 4.2.3.1 Electrosorption/desorption profiles of the Fe/HrGO composite	71
Figure 4.3.1.1 Electrosorption/desorption of the Fe/HrGO electrode in 50 ppm PbCl2 solution.	73
Figure 4.3.2.1 Electrosorption/desorption of the Fe/HrGO electrode in 50 ppm CuCl2 solution (0.8 V).	75
 
List of Table
Table 3.2.1.1 Manufacturers and purity of experimental chemicals.	23
Table 3.2.2.1 Manufacturers and model of instrument.	24
Table 4.1.1.1 Surface and porosity characteristics of Fe/HrGO (Microwave synthesis).	45
Table 4.1.1.2 Contact angle analyses of Fe/HrGO (Microwave synthesis).	46
Table 4.1.2.1 Mass normalized specific capacitance (F/g) of Fe/HrGO (Microwave	48
Table 4.1.3.1 Removal efficiency (%) and electrosorption capacity (mg/g) of the Fe/HrGO (microwave synthesis) composite electrode in 250 ppm NaCl (1.0V)	55
Table 4.2.1.1 Surface and porosity characteristics of HrGO and Fe/HrGO.	62
Table 4.2.1.2 Contact angle analyses of HrGO and Fe/HrGO.	62
Table 4.2.2.1 Mass normalized specific capacitance (F/g) of Fe/HrGO composites	64
Table 4.2.3.1 Electrosorption-desorption cycles of Removal efficiency (%) and	71
Table 4.3.1.1 Electrosorption-desorption cycles of Removal efficiency (%) and	73
Table 4.3.2.1 Electrosorption-desorption cycles of Removal efficiency (%) and	75
Table 5.1 Comparison of characteristics and CDI performance of microwave synthesis or hydrothermal synthesis Fe/HrGO composites.	...77

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