2000 Fiscal Year Final Research Report Summary
A study on thermally and chemically stable multifunctional membranes
| Project/Area Number |
10305060
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A).
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
触媒・化学プロセス
|
|---|
| Research Institution | TOHOKU UNIVERSITY |
|---|
Principal Investigator |
TOMITA Akira Institute for Chemical Reaction Science, Tohoku University, Professor, 反応化学研究所, 教授 (80006311)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KYOTANI Takashi Institute for Chemical Reaction Science, Tohoku University, Associate Professor, 反応化学研究所, 助教授 (90153238)
|
|---|
| Project Period (FY) |
1998 – 2000
|
| Keywords | anodic aluminum oxide film / membrane filter / pervaporation separation / carbon deposition / chemical modification |
|---|
| Research Abstract |
The porosity of an anodic aluminum oxide film consists of an array of parallel and straight channels with a uniform diameter at nanometer level. Because of the presence of such nanochannels, the film has been used as a membrane for ultrafilitration. This membrane filter however, suffers from its poor chemical stability both in acid and alkaline solutions. In order to circumvent such poor stability, we have prepared a carbon-coated membrane from an anodic oxide film and then chemically-modified its carbon surface by either oxidation or fluorination treatment. In the present study, we use the membrane for pervaporation separation of water/ethanol mixture and investigate the effect of such modification on the pervaporation performance.
When pyrolytic decomposition of propylene was carried out over an anodic aluminum oxide film, uniform carbon coating on the film was achieved. The carbon deposition process decreased the channel diameter from 30 to 20 nm, but left the whole channel structure intact. Further fluorination or HNO_3 treatment did not alter the channel structure. Gas permeation through these films was found to be principally governed by Knudsen diffusion. In the pervaporation separation of water/ethanol mixture, preferential permeation of water was observed in the fluorinated films, although the untreated and oxidized carbon-coated films did not show any selectivity. This work demonstrated that, even if pore diameter is as large as 20 nm, a suitable surface modification to pore wall makes it possible to endow a membrane with selectivity in pervaporation separation.
|
