本研究以聚偏二氟乙烯(poly(vinylidene fluoride), PVDF)膜材，並使用親水支撐層合成一平板親-疏水複合薄膜，來組裝模組進行直接接觸式薄膜蒸餾(Direct Contact Membrane Distillation, DCMD)用於海水淡化之效能探討，進料之模擬海水為3.5 wt%的NaCl水溶液。合成薄膜的組成為PVDF、磷酸三乙酯(Triethyl phosphate, TEP)及Tween-20的混合溶液，其中共四種條件分別為10、20、40、60 wt%磷酸三乙酯(TEP)水溶液，藉由硬性沉澱槽換成軟性沉澱槽的方式來改善平板薄膜表面結構。從SEM解析得知隨著磷酸三乙酯(TEP)在沉澱槽的比例增加薄膜表面大孔洞數量，探討其薄膜結構對蒸餾操作之影響。
在實驗操作部分主要是探討不同的參數對薄膜蒸餾之滲透通量及鹽阻隔率之影響，DCMD中兩側流體流動是逆流方式，其它參數包括在進料溫度(50~70 oC)、進料速度(0.4~0.7 L/min)與不同進料濃度(純水~15wt%NaCl溶液)。
在DCMD中其結果顯示隨著沉澱槽TEP wt%的比例增加，所製成的薄膜之通量皆會高於沒改質的薄膜，是由於隨著TEP在沉澱槽的比例增加薄膜表面皮層結構不易形成，且大孔洞數變多。且提高進料溫度能明顯增加滲透通量，但極化現象也較嚴重，而增加進料流率則對於滲透通量之提升較不顯著，但對於高溫進料操作之溫度極化現象具有較明顯改善效果。

In this study, the flat-sheet composite membranes of polyvinylidene fluoride (PVDF) supported on hydrophilic cellulose were prepared, and their performances in direct contact membrane distillation (DCMD) for seawater desalination were also investigated.  
The simulated seawater of 3.5 wt% NaCl solution was adepted as the feed. The dope solution consisted of PVDF, Triethyl phosphate(TEP) and Tween-20, and four conditions, 10、20、40 and 60 wt% triethylphosphate (TEP) solution were applied in the coagulation bath. From the observation by SEM, the surface pore sizeof membrane increased with the increasing of TEP concentration in the coagulation bath.  
The experimental results of DCMD showed that the membrane prepared from higher TEP concentration had a larger permeate flux because of its larger pore size on the surface. And increasing the feed temperature of the feed can significantly increase the flux, but the polarization phenomena become more serious, but the effect of increasing feed flow rate the effect is not obvious on the flux.

目錄
誌謝…………………………………………………………………………………I
中文摘要……………………………………………………………………………II
英文摘要……………………………………………………………………………III
目錄…………………………………………………………………………………IV
圖目錄………………………………………………………………………………VI
表目錄………………………………………………………………………………VIII
第一章  緒論………………………………………………………………………1
1.1	前言……………………………………………………………………………1
1.2	薄膜分離程序…………………………………………………………………2
1.3	薄膜的應用……………………………………………………………………4
1.4	薄膜蒸餾………………………………………………………………………7
1.5	研究目標………………………………………………………………………9
第二章  文獻回顧…………………………………………………………………12
2.1	薄膜蒸餾研究…………………………………………………………………12
2.2	薄膜蒸餾法之種類……………………………………………………………16
2.2.1  直接接觸式薄膜蒸餾………………………………………………………16
2.2.2  空氣間隙式薄膜蒸餾………………………………………………………16
2.2.3  空氣掃掠式薄膜蒸餾………………………………………………………17
2.2.4  真空式薄膜蒸餾……………………………………………………………17
2.3	薄膜孔洞結構及性質…………………………………………………………17
2.4	影響滲透通量的因素…………………………………………………………19
2.5	薄膜製備………………………………………………………………………21
2.6	高分子成膜理論………………………………………………………………22
2.6.1   成膜理論: 熱力學…………………………………………………………22
2.6.2   成膜理論: 質傳動力學……………………………………………………24
第三章	實驗裝置與方法…………………………………………………………27
3.1	實驗裝置………………………………………………………………………27
3.2	薄膜製備………………………………………………………………………28
3.3	薄組編號………………………………………………………………………28
3.4	薄膜性質分析…………………………………………………………………29
3.4.1  薄膜型態和表面孔洞分析…………………………………………………29
3.4.2  薄膜膜厚及孔隙度測試……………………………………………………29
3.4.3  接觸角量測…………………………………………………………………29
3.5	DCMD實驗步驟………………………………………………………………30
3.6	DCMD操作條件………………………………………………………………32
3.7	分析方法………………………………………………………………………33
3.7.1  鹽類含量之分析方法與條件………………………………………………33
3.7.2  鹽類阻隔率之計算…………………………………………………………33
3.8	流量計校正……………………………………………………………………33
3.9	實驗設備及藥品………………………………………………………………34
第四章	結果與討論………………………………………………………………45
4.1	薄膜特性與結構分析…………………………………………………………45
4.1.1	薄膜(鑄膜於支撐層)結構…………………………………………………45
4.1.2	薄膜(鑄膜於玻璃板)結構…………………………………………………47
4.1.3	薄膜之孔隙度………………………………………………………………47
4.1.4	薄膜之接觸角………………………………………………………………47
4.2	DCMD薄膜蒸餾………………………………………………………………56
4.2.1	DCMD滲透通量…………………………………………………………56
4.2.2	不同刮膜厚度的影響………………………………………………………61
4.2.3	鑄膜於親水支撐層與玻璃板上之比較……………………………………63
4.2.4	鹽水濃度的影響……………………………………………………………67
4.2.5	複合薄膜回洗後回復性之探討……………………………………………69
4.3	薄膜阻隔率……………………………………………………………………72
4.4	DCMD系統與文獻之比較……………………………………………………74
第五章	結論………………………………………………………………………75
參考文獻……………………………………………………………………………79
附錄A………………………………………………………………………………87









圖目錄
圖1.1   薄膜分離程序之分類……………………………………………………10
圖1.2   薄膜蒸餾物流流動示意圖………………………………………………11
圖2.1	薄膜蒸餾膜組之型式……………………………………………………25
圖2.2	高分子(非結晶型)-溶劑-非溶劑成膜相圖………………………………26
圖2.3	Schematic representation of mass transfer occurring at the membrane/coagulant surface [Mulder, 1991；Lin and Wang , 1996]………26
圖3.1	DCMD 模組示意圖………………………………………………………36
圖3.2	DCMD 模組設計示意圖(進料側)………………………………………37
圖3.3	DCMD 模組設計示意圖(冷卻水側)……………………………………38
圖3.4	DCMD experiment set up………………………………………………39
圖3.5  親水支撐層之SEM結構圖………………………………………………40
圖3.6	進料流體流量計校正曲線………………………………………………41
圖3.7	冷卻水流體流量計校正曲線……………………………………………41
圖4.1	添加不同比例之TEP於沉澱槽500倍之薄膜截面……………………49
圖4.2	添加不同比例之TEP於沉澱槽10000倍之薄膜截面…………………50
圖4.3	添加不同比例之TEP於沉澱槽5000倍之薄膜上表面…………………51
圖4.4	添加不同比例之TEP於沉澱槽10000倍之薄膜上表面………………52
圖4.5	添加20wt%之TEP於沉澱槽5000倍之薄膜上表面……………………53
圖4.6	添加20wt%之TEP於沉澱槽10000倍之薄膜截面……………………54
圖4.7	T60於DCMD之滲透通量………………………………………………58
圖4.8	鹽水於50~70 oC & 0.7 L/min進料速率下DCMD之滲透通量………58
圖4.9	鹽水於50 oC 在不同進料速率下DCMD之滲透通量…………………59
圖4.10	鹽水於60 oC在不同進料速率下DCMD之滲透通量…………………59
圖4.11	鹽水於70 oC在不同進料速率下DCMD之滲透通量…………………60
圖4.12 不同刮刀厚度DCMD之滲透通量比較(T_f=50-70℃, u_f=0.7 L/min)…62
圖4.13	刮刀厚度200μm鑄膜於支撐層與玻璃板DCMD之滲透通量比較比較(T_f=50-70℃, u_f=0.7 L/min)…………………………………………………65
圖4.14	刮刀厚度300μm鑄膜於支撐層與玻璃板DCMD之滲透通量比較比較(T_f=50-70℃, u_f=0.7 L/min)…………………………………………………65
圖4.15	刮刀厚度400μm鑄膜於支撐層與玻璃板DCMD之滲透通量比較比較(T_f=50-70℃, u_f=0.7 L/min)…………………………………………………66
圖4.16 鹽水濃度對DCMD滲透通量的影響(T_f=50℃, u_f=0.5 L/min)……68
圖4.17	M-200-T20於70 oC在不同進料速率下不同鹽水濃度(3.5wt%、10wt%、15wt%)前後純水DCMD之滲透通量…………………………………………70
圖4.18	M-200-T40於70 oC在不同進料速率下不同鹽水濃度(3.5wt%、10wt%、15wt%)前後純水DCMD之滲透通量…………………………………………70
圖4.19	M-200-T60於70 oC在不同進料速率下不同鹽水濃度(3.5wt%、10wt%、15wt%)前後純水DCMD之滲透通量…………………………………………71
圖4.20	T20薄膜於50 oC進行兩天DCMD之通量及導電度…………………73
圖4.21	T60薄膜於50 oC進行兩天DCMD之通量及導電度…………………73
圖4.22	T60於DCMD與其他論文滲透通量之比較…………………………75
圖A   NaCl檢量線………………………………………………………………87


表目錄
表1.1 	不同操作程序之驅動力分類[Cheryan, 1998]…………………………10
表3.1	製膜液組成與製備條件…………………………………………………42
表3.2	親水支撐層性質說明……………………………………………………43
表3.3	Characteristics of membrane module…………………………………44
表4.1	PVDF薄膜基本結構與物性分析………………………………………55
表4.2	Comparison of DCMD results between literatures……………………76

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