2020 Fiscal Year Final Research Report
Characterization of active layer of reverse osmosis membrane by electrochemical impedance spectroscopy in quasi-filtration conditions
| Project/Area Number |
18K04809
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 27010:Transport phenomena and unit operations-related
|
|---|
| Research Institution | Shinshu University |
|---|
Principal Investigator |
Tanaka Atsushi 信州大学, 学術研究院工学系, 教授 (30417878)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
手嶋 勝弥 信州大学, 学術研究院工学系, 教授 (00402131)
竹内 健司 信州大学, 学術研究院工学系, 准教授 (20504658)
巽 広輔 信州大学, 学術研究院理学系, 教授 (60336609)
|
|---|
| Project Period (FY) |
2018-04-01 – 2021-03-31
|
| Keywords | 逆浸透膜 / 活性層 / 電気化学インピーダンス法 / イオン伝導 / Maxwell-Wagner Model / 透水状態 / 膜劣化 |
|---|
| Outline of Final Research Achievements |
The complex impedance spectrum of a free-standing reverse osmosis (RO) membrane with a polyamide active layer was measured and analyzed. In the case of RO membranes immersed in a 10 mmol / L KCl electrolyte, the active layer spectrum was observed below 2 kHz. According to the Maxwell-Wagner model, the measurement data was fitted and the resistance and capacitance of each layer were estimated using an equivalent circuit model. In the cross-flow filtration state, divalent electrolyte, MgCl2 was injected into the permeation side prior to the impedance measurement. This is because the low ion concentrations of support/no-woven layer makes it difficult to measure the active layer spectrum. This method was very effective in measuring the spectrum of the active layer without affecting the ionic conduction of the active layer. Using this method, we succeeded in quantifying the decrease in the resistance of the active layer by measuring the deteriorated RO membrane exposed to chloride ions.
|
| Free Research Field |
工学
|
| Academic Significance and Societal Importance of the Research Achievements |
浸漬状態および準透水状態で活性層／支持層／不織布の積層状態で複素インピーダンスを測定し、活性層のスペクトルを分離・解析が可能となった。透水稼働状態におけるマクロな活性層のイオン選択透過性とインピーダンス測定による活性層のイオン伝導の定量評価を同一の評価系で同時に結び付ける評価が可能となったことは、RO膜の特性をメゾスコピックに解析、理解することにつながり、学術的に大きな意義がある。芳香族ポリアミドRO膜の塩素イオン暴露の前後でのスペクトル変化も確認できた。アミド結合の損傷の初期過程や耐塩素性を有する膜の設計開発などにも寄与する先進的膜評価手法として工学的にも意義がある。
|
