脈衝式水溶液電漿性質檢測及孔性金屬有機骨架製程研究

Abstract

本研究對於脈衝式水溶液電漿系統進行檢測，並嘗試以水溶液電漿製備材料。使用脈衝式電源驅動相較於直流或交流的供應能提供水溶液電漿系統具有更穩定且更佳的再現性表現，此性質使其具有被應用於系統檢測或材料製備的潛力，可藉由調控脈衝式電源之操作參數，控制系統在適當的條件下進行反應。實驗內容分為兩個部分，第一部分為診斷水溶液電漿系統之表現對應於驅動電極與溶液直接接觸面積的影響，第二部分為使用水溶液電漿系統製備類沸石咪唑材料。 第一部分以脈衝式電源激發電漿在 0.1 M 氯化鈉(NaCl)水溶液中生成，分別在驅動電極截面積直徑為0.1、0.3、0.5及1釐米系統中，進行同步化電流電壓、電漿放射光、氣泡動態及單位面積功率耗損的分析。氣泡在電極表面的生成速率與透過積分示波器所紀錄之電流電壓得到的單位面積能量耗損成正比，不受工作時間(Ton)的影響，而單位面積能量耗損則與驅動電極直接接觸溶液的面積成反比，造成在固定工作時間內，氣泡及電流波峰的出現頻率在小電極截面積直徑系統中較高，藉由同步相機與示波器觀察得到電流波峰與氣泡形成機制間存在重要關聯，且此現象與文獻中使用直流電源作驅動的電漿表現一致，而電漿放射光的生成機制不因系統不同而改變，皆伴隨氣泡的破裂或收縮出現，藉由上述之檢測試圖解釋水溶液電漿系統之概要性表現。 第二部分嘗試以脈衝式水溶液電漿，在水相中低反應物濃度條件下製備類沸石咪唑材料，透過以微流體方式注入金屬陽離子，在金屬鹽類溶液及有機配位子溶液接觸區域以電漿進行處理，並在純化過程中之離心與蒸乾步驟中採用甲醇作為溶劑，即本製程於前段反應在水相而於後段純化則在有機相中進行，經過XRD、SEM及FTIR的分析，得到實驗的最終產物為高純度之類沸石咪唑材料，提供一在水相環境中，於短時間內即能在低反應物濃度下合成高純度類沸石咪唑材料的製程。

The diagnosis of plasma generated by a pulsed voltage in NaCl electrolytic solution and its potential applications are studied. The pulsed power can offer the solution plasma system a better stability and cycle-to-cycle reproducibility than the performance driven by DC or AC power. The optimum plasma behavior can be represented by regulating the suitable operation parameters, and this advantage gives a potential opportunity of the application for the system diagnosis and material fabrication. The experimental investigations include two parts: Diagnostic study of the effect of the electrode diameter on the behavior of plasmas and Synthesis of metal-organic frameworks by using aqueous solution plasma. In the first part, the effect of the electrode diameter on the discharge behavior of plasmas in saline solution was studied. The measurement of the plasma performance including current and voltage waveforms, discharge emissions, bubble dynamics and power consumptions were detected in the system. The driving electrode was a platinum wire covered by a glass tube to precisely define the area exposed to the solution. Platinum wires of four different diameters, namely 0.1 mm, 0.3 mm, 0.5 mm, and 1 mm, were used. A positive correlation was found between the generating rate of the bubble on the electrode surface and the power density consumption calculated from the IV waveform recorded by the oscilloscope. The result didn’t depended on the working period (Ton). However, a negative correlation existed between the area of the driving electrode exposed to the solution and the power density consumption. The outcome may explain why a higher appearance frequency of the bubbles and the current peaks in the small diameter driving electrode system. The time-resolved bubble dynamics taken by the high speed video show that the vapor formation process in this experiment is the same as the one driven by a DC power supply. The bubble formation mechanism is strong related to the change of the current waveform. The plasma discharges would not form until the vapor layer collapse or shrink in each system. The observations done in the experiment offer an explanation of the general solution plasma behaviors. In the second part, we tried to synthesize metal-organic frameworks by using aqueous solution plasma. The object of this experiment was to develop a fabrication which could synthesize high purity metal-organic frameworks in the conditions of low concentration of the reactants and reduced time. An attempt that the zinc salt microfluidics was introduced to the reaction container and a plasma was ignited in the contact zone between the zinc salt solution and the ligand solution was approached. After the reactants were treated in the aqueous phase, they were dissolved in the methanol for centrifugation and drying. The pure products were confirmed by analyzing the XRD, SEM and FTIR patterns. The experiment results supported that we reach the goal.