| 研究実績の概要 |
This work investigates the complexity and importance of thin-film composite (TFC) membranes that contain ultrathin layers in the structure. At the beginning stage, the focus was to examine how the surface modification of the hydrophobic polymer layer by water vapor-generated plasma influences the formation of the selective interface with the hydrophilic selective layer. We discovered that a minimum critical amount of surface modification is crucial to form the proper laminate structure. However, we also found that the surface modification by the plasma treatment alone does not increase the membrane's selectivity towards CO2 and the optimal combination with selective polymer is essential.
This research then studies the gas transport of CO2, O2, and N2, to identify the extent of the molecular interface in achieving highly selective CO2/N2 and CO2/O2 separation. With the inclusion of this selective interface in the TFC structure, the selectivity significantly increased. For instance, the selectivity for CO2/N2 and CO2/O2 separation reached approximately 35 and 13, respectively, compared to ~10 and ~5 in the membranes without the selective layer and interface. Importantly, our work also focuses on the application of these membranes in the direct air capture of CO2, a technology that plays a vital role in mitigating the effects of climate change. By capturing carbon dioxide directly from the air, we can effectively reduce the concentration of greenhouse gases in the atmosphere, thereby slowing down the rate of global warming.
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| 今後の研究の推進方策 |
The conditions of the selective interface formation between the highly permeable hydrophobic polymer (PDMS) and CO2 selective hydrophilic polymer poly(block-amide-ethylene oxide) were established. The influence of the surface modification by oxygen and water plasmas was systematically studied. In the next research stage, we study the influence of the thicknesses of polymeric layers and overal membrane geometry of the thin-film composite membrane. We will continue to systematically investigate the thickness's impact on interface formation and its contribution to the CO2 selectivity and, overall gas separation performance.
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