2023 年 48 巻 1 号 p. 38-48
In response to a request to write about the history of my membrane technology research, I decided to write a three–part series. I started my research on membrane technology in 1974, about 50 years ago. It was around the time when membranes were not commercially available in Japan, and seawater desalination using reverse osmosis was just beginning to be put into practical use in the United States. Since then, I have researched various things about membranes, so I can’t write everything in three articles. Of course, there are some studies that did not produce good results and were forgotten. Therefore, instead of writing about the research conducted in chronological order, I divided the research themes broadly and decided to write about each of them. In this first installment, I will write about membrane fouling and transport equations for membrane permeation, which are areas in which I have conducted experiments and analyzed myself. Concerning fouling of membranes, I showed flux behavior by fouling when sewage treated water is treated with reverse osmosis and I demonstrated that the gel layer concentration was not constant, which was believed to be constant in the gel layer model. Moreover, I explained that the characteristic phenomena of fouling could be explained only by osmotic pressure. These discoveries were the first in the world at the time, but are now common knowledge and are written in every textbook. As for the transport equation, I proved the effectiveness of the 3–parameter transport equation as an alternative to the 2–parameter transport equation proposed by my teacher, Professor Shoji Kimura, and proposed a pore model that connects the parameters and the membrane pore structure.