Tremendous progress in two-dimensional (2D) nanomaterial chemistry affords abundant opportunities for the sustainable development of membranes and membrane processes. In this review, we propose the concept of mixed dimensional membranes (MDMs), which are fabricated through the integration of 2D materials with nanomaterials of different dimensionality and chemistry. Complementing mixed matrix membranes or hybrid membranes, MDMs stimulate different conceptual thinking about designing advanced membranes from the angle of the dimensions of the building blocks as well as the final structures, including the nanochannels and the bulk structures. In this review, we survey MDMs (denoted nD/2D, where n is 0, 1 or 3) in terms of the dimensions of membrane-forming nanomaterials, as well as their fabrication methods. Subsequently, we highlight three kinds of nanochannels, which are 1D nanochannels within 1D/2D membranes, 2D nanochannels within 0D/2D membranes, and 3D nanochannels within 3D/2D membranes. Strategies to tune the physical and chemical microenvironments of the nanochannels as well as the bulk structures based on the size, type, structure and chemical character of nanomaterials are discussed. Some representative applications of MDMs are illustrated for gas molecular separations, liquid molecular separations, ionic separations and oil/water separation. Finally, current challenges and a future perspective on MDMs are presented.

中文翻译：

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混合维膜：化学和结构-性能关系

二维 (2D) 纳米材料化学的巨大进步为膜和膜工艺的可持续发展提供了丰富的机会。在这篇综述中，我们提出了混合维膜 (MDM) 的概念，它是通过将 2D 材料与不同维数和化学性质的纳米材料集成而制成的。作为混合基质膜或混合膜的补充，MDM 激发了不同的概念性思考，从构建块的尺寸以及最终结构（包括纳米通道和体结构）的角度来设计先进的膜。在本次审查中，我们调查了 MDM（表示为n D/2D，其中n在成膜纳米材料的尺寸及其制造方法方面为0、1或3）。随后，我们重点介绍了三种纳米通道，即 1D/2D 膜内的 1D 纳米通道、0D/2D 膜内的 2D 纳米通道和 3D/2D 膜内的 3D 纳米通道。讨论了基于纳米材料的尺寸、类型、结构和化学特性来调整纳米通道的物理和化学微环境以及体结构的策略。MDMs 的一些代表性应用被说明用于气体分子分离、液体分子分离、离子分离和油/水分离。最后，介绍了 MDM 的当前挑战和未来前景。