Polyimide-based membranes for gas separation applications

Polymer membranes have emerged as a promising technology for gas separation in a variety of industrial and environmental applications. They offer a number of advantages over traditional methods, such as cryogenic distillation and absorption, including lower energy consumption, smaller footprint, and easier operation. Polymer membranes work by selectively permeating different gases at different rates. This is achieved by designing membranes with specific properties, such as pore size and surface chemistry. The most common types of polymer membranes for gas separation are dense and hollow fiber membranes. Dense membranes separate gases based on their solubility and diffusion in the polymer matrix, while porous membranes separate gases based on their molecular size and shape. Polymer membranes are used in a wide range of gas separation applications, including natural gas sweetening, air separation, hydrogen recovery, and carbon capture and storage. One of the key challenges in developing polymer membranes for gas separation is to achieve a balance between permeability and selectivity that overcomes the trade-off behavior. Researchers are developing new polymer membranes with improved permeability and selectivity through a variety of approaches, such as designing new polymer materials with tailored properties, developing composite membranes that combine different polymers or materials, and modifying the surface of polymer membranes to improve their separation performance. With continued research and development, polymer membranes are expected to become even more efficient and cost-effective, making them even more attractive for a wider range of applications. In this chapter, we review the involvement of polyimides in the preparation of dense membranes for gas separation. The chapter discusses the synthesis of polyimides and their gas separation performance.