Abstract Two-dimensional titanium carbides, known as MXenes, have attracted growing attention in membrane research community. In this study, a typical MXene, Ti3C2Tx, is incorporated Pebax to fabricate mixed matrix membranes, for CO2 separation, with GO-filled membranes as reference. It is found that MXene-filled membranes afford much higher loading (up to 20 wt%) than GO-filled ones (up to 5 wt%) due to the rich polar groups at MXene surface and the resultant better interfacial interactions. More interestingly, dry-state membranes exhibit the optimal CO2 separation performance at quite low loading (at 1 wt%) for both GO and MXene, which is often seen in Pebax-based mixed matrix membranes, while the permeability and CO2/N2 selectivity of wet-state membranes proceed to increase when filler loading reaches 5 wt% or above, which represents an unusual comparison with the results collected under dry conditions. Since GO and MXene are used without any functionalization, such enhancement of CO2 separation performance at high loading under humidification can be only attributed to the hydrated interlayer channels of MXene/GO. These findings show the unique characteristics of 2D fillers, especially MXene, in wet-state mixed matrix membranes for CO2 separation, and also provide new information to better understand the roles of fillers in Pebax at different content or under different conditions.

中文翻译：

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MXene 与氧化石墨烯：研究二维纳米片在混合基质膜中对 CO2 分离的影响

摘要 二维碳化钛，即MXenes，在膜研究界引起了越来越多的关注。在这项研究中，典型的 MXene Ti3C2Tx 与 Pebax 结合以制造混合基质膜，用于 CO2 分离，并以 GO 填充膜作为参考。发现由于 MXene 表面富含极性基团和由此产生的更好的界面相互作用，MXene 填充的膜提供比 GO 填充的膜（高达 5wt%）更高的负载（高达 20 wt%）。更有趣的是，对于 GO 和 MXene，干态膜在相当低的负载量（1 wt%）下表现出最佳的 CO2 分离性能，这在基于 Pebax 的混合基质膜中很常见，而渗透性和 CO2/N2 选择性为当填料含量达到 5 wt% 或以上时，湿态膜继续增加，这代表了与在干燥条件下收集的结果不同寻常的比较。由于 GO 和 MXene 的使用没有任何功能化，因此在加湿条件下高负载下 CO2 分离性能的增强只能归因于 MXene/GO 的水合层间通道。这些发现显示了二维填料，尤其是 MXene，在用于 CO2 分离的湿态混合基质膜中的独特特性，也为更好地了解填料在不同含量或不同条件下在 Pebax 中的作用提供了新信息。