Confined mass transfer refers to the mass transfer behavior of fluids in spaces whose characteristic dimensions are comparable to the molecular mean free path. In the field of membrane separation, when the characteristic dimensions of membrane pores decrease to a certain scale, the membrane pores become confined spaces for fluid transport. Under confinement, the effects of pore walls on fluid molecules, which would otherwise be negligible, become significantly enhanced, thereby exerting pronounced effects on permeability and selectivity and becoming important or even decisive factors governing the transport process. The resulting anomalous mass transfer phenomenon is referred to as the confined mass transfer effect. Separation membranes based on confined mass transfer are mainly used for the separation of homogeneous solution or gas systems and involve high-precision separation processes at the molecular/ionic level, such as gas separation including carbon dioxide separation, pervaporation, and nanofiltration. One of the keys to achieving efficient molecular separation is the construction and regulation of sub-nanometer mass transfer channels in separation membranes based on confined mass transfer.
This presentation will focus on separation membranes based on confined mass transfer, including two-dimensional material membranes, metal-organic framework membranes, and organic/inorganic composite membranes, which possess fast and selective transport channels for gas, water, and solvent molecules. It will discuss how theories and methods from materials science, physical chemistry, and mathematics can be integrated to construct sub-nanometer mass transfer channels in separation membranes and to explore the mass transfer mechanisms of molecules and ions within the sub-nanometer channels of confined mass transfer membranes, thereby enabling efficient molecular-scale separation.
