Effects of surface chemistry on pressure drop by permeation of water through nano/micro porous structure

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05119
• 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: Yokohama National University
• Principal Investigator: Nakamura Kazuho 横浜国立大学, 大学院工学研究院, 准教授 (30323934)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: ろ過 / 膜分離 / 水処理 / 電気粘性効果 / 界面動電現象 / 電気二重層 / 多孔質膜 / 圧力損失

Outline of Final Research Achievements

The purpose of this study was to develop a new interfacial scientific understanding of pressure loss that occurs when a liquid permeates a fine gap (nano-microspace) in a porous membrane or filtration cake, and a pressure loss reduction method based on that understanding. As a result of examining in detail the effect of KCL concentration on the pressure drop of porous glass membrane, a tendency for pressure drop to increase in the low concentration range close to pure water was observed, which was explained by the electro viscosity effect that apparently increases the viscosity of the liquid with the overlap of the electric double layer developed in the pores. The surface modification and surfactant adsorption on this electro viscosity effect were examined and it was found that the no-charge and hydrophobic surfaces reduce the electric viscosity effect, and a new pressure drop reduction method based on interface control was proposed based on this finding.

Free Research Field

分離工学

Academic Significance and Societal Importance of the Research Achievements

生活排水の処理や工業用の純水製造など多くの分野で多孔質膜を用いた膜ろ過操作が用いられて、水環境の保全や先端科学産業を基礎から支えている。このような、分離プロセスではエネルギーの消費が大きなことが最大の課題であり、エネルギーは液体がろ過膜やケーク層の中の微細な空間を透過する際に生じる圧力損失として消費される。プロセスの省エネルギー化のために圧力損失の根本的な現象について電気粘性効果に基づく理解を行った。さらに電気粘性効果を利用した新しい圧力損失の低減方法を提案し、この方法を応用することにより、従来にはない非常に簡便な方法でろ過プロセスの省エネルギー化を達成することができる。