2019 Fiscal Year Annual Research Report
Magnetic separation of oxygen from air
| Project/Area Number |
19F19043
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
POURNAGHSHBAND ISFAHANI ALI 京都大学, 高等研究院, 外国人特別研究員
|
|---|
| Project Period (FY) |
2019-04-25 – 2021-03-31
|
| Keywords | Gas separation membrane / MXene / Molecular sieving / H2/CO2 separation |
|---|
| Outline of Annual Research Achievements |
Herein, we used a new family of 2D material (Ti3C2Tx MXene) for gas membrane application to take advantage of its sub-nanometer d-spacing and the functional groups on the surface. The main challenge to obtain a high separation performance 2D membranes is non-selective defects that form between randomly adjacent stacked nanosheets. Vacuum filtration on AAO substrate was chosen as the best method to improve the interlocking MXene laminates and avoid undesirable defects. The membrane thickness was adjusted between 20 nm to 100 nm with an exact volume of MXene suspension.
Gas permeation of MXene membranes was conducted by a Wicke Kallenbach permeation cell. H2 permeance and H2/CO2 selectivity of AAO support were 15000 GPU and ~5, respectively, similar to the Knudsen selectivity of H2/CO2 (4.7). H2 permeance of the membranes with a thickness of~40 nm was about 7800 GPU, while other gases with larger molecular size showed much lower permeances. Accordingly, the H2/CO2 ideal selectivity reached 115, far exceeded the H2/CO2 Knudsen selectivity and the most current membranes. Although the smaller molecular size, the CO2 permeance was about four times lower than N2 and O2. The low CO2 permeance and O2/N2 selectivity can be ascribed to the preferential adsorption of CO2, decreasing the diffusional mobility.
The gas permeance of the MXene membranes varied by the thickness between 9000 to 3300 GPUs along with the variation of H2/CO2 selectivity from 50 to 320, which can be attributed to the increased MXene platelets and sieving ability.
|
| Current Status of Research Progress |
Current Status of Research Progress
4: Progress in research has been delayed.
Reason
The safety issues of using HF for etching the aluminum metal from the MAX phase did not allow us to synthesize our powder at Kyoto University. On the other hand, finding a reliable source to order a fresh and high-quality MXene suitable for gas membrane application was difficult and took few months. Also, we had not been allowed to use lab facilities for a two-month period because of the pandemic.
|
| Strategy for Future Research Activity |
Improving the selectivity of MXene membranes by tuning the d-spacing interlayer has been planned. The mixture of MXene and graphene oxide (GO) at different compositions has been considered. It is supposed that MXene platelets can interact with GO sheets through covalent and hydrogen bonding. This research aims to improve the alignment degree of the MXene layers and reduce the channel size to increase the sieving ability. Besides, the strong interaction between the two components would enhance the stability and mechanical properties of the MXene membranes.
|
