Elucidation of membrane fouling mechanism in forward osmosis and mitigating effects of advanced oxidation processses

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14275
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Nomura Youhei 京都大学, 地球環境学堂, 助教 (30869730)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 正浸透法 / 下水二次処理水 / 三酢酸セルロース活性層 / 濃縮 / 膜ファウリング

Outline of Final Research Achievements

The effects of cross-flow rate and inorganics concentration on the permeate flux were investigated to clarify the characteristics of concentrating treated sewage effluent by forward osmosis. Increase in the cross-flow rate (10.7~100 mm/s) mitigated the decrease in the permeate flux with the membrane fouling and concentrated treated sewage effluent efficiently. Increase in the calcium ion concentration resulted in the decrease in the permeate flux and formation larger-molecular-weight organic compounds. The photocatalysis using titanium dioxide converted the larger-molecular-weight organic compounds to lower-molecular-weight organic compounds and mitigated the decrease in the permeate flux. This shows that the photocatalysis is effective in mitigating the membrane fouling.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

既往研究では、モデル有機物(多糖類やタンパク質など)を含む模擬下水や模擬廃水に対して、カルシウムのような無機物を添加することで、ファウリング発生機構が調査されてきたが、実際の下水中や廃水中の膜ファウリングの挙動を再現できないことが報告されてきた。本研究課題では、実際の下水処理水に無機物を添加し、無機物が膜透過水fluxに及ぼす影響を明らかにするとともに、光触媒を用いた促進酸化処理を行うことで膜ファウリングを低減できることを明らかとし、新たな学術的知見を得た。