A comprehensive overview of dual-layer composite membrane for air (O2/N2) separation

The separation of air (O2/N2) via a polymeric membrane has recently piqued the interest of academic researcher as well as the industrial sector. Because of its remarkable characteristics, the polymeric membrane has emerged as one of the innovative and fast growing technology. However, two major problems faced by membrane technology, which hinder its growth in the commercial sector are, 1): The trade-off between permeability and selectivity. 2): Maintaining physical and chemical structural stability in a long-term commercial scale process. Recent advancements in membrane material, structural, and process design have enabled the development of dual-layer composite (DLC) membranes. This concept combines the benefits of both thinner mixed matrix membranes (MMMs) based active layer and porous support substrate. Due to these properties, the membrane exhibits higher perm-selectivity with enhanced mechanical strength as compared to single layer polymeric membrane. This review article mainly focused on the developmental progress of DLC membrane throughout the years. In which membrane structural details, selection criteria, fabrication methodologies, application [e.g., air (O2/N2) separation] were critically reviewed. In addition, challenges arising in the DLC membrane production and future prospects for the development of these membranes were also thoroughly discussed in this literature. This creates a paradigm for future research in the commercial development of these membranes for the air (O2/N2) separation process, which can be utilized in both medical and industrial sectors.