Permeation properties of CO 2 and CH 4 in asymmetric polyethersulfone/polyesterurethane and polyethersulfone/polyetherurethane blend membranes

Recent advancements in polyurethane-based membranes for gas separation

Gas separation membranes are critical in a variety of environmental research and industrial applications. These membranes are designed to selectively allow some gases to flow while blocking others, allowing for the separation and purification of gases for a variety of applications. Therefore, the demand for fast and energy-efficient gas separation techniques is of central interest for many chemical and energy production diligences due to the intensified levels of greenhouse and industrial gases. This encourages the researchers to innovate techniques for capturing and separating these gases, including membrane separation techniques. Polymeric membranes play a significant role in gas separations by capturing gases from the fuel combustion process, purifying chemical raw material used for plastic production, and isolating pure and noncombustible gases. Polyurethane-based membrane technology offers an excellent knack for gas separation applications and has also been considered more energy-efficient than conventional phase change separation methodologies. This review article reveals a thorough delineation of the current developments and efforts made for PU membranes. It further explains its uses for the separation of valuable gases such as carbon dioxide (CO2), hydrogen (H2), nitrogen (N2), methane (CH4), or a mixture of gases from a variety of gas spillages. Polyurethane (PU) is an excellent choice of material and a leading candidate for producing gas-separating membranes because of its outstanding chemical chemistry, good mechanical abilities, higher permeability, and variable microstructure. The presence of PU improves several characteristics of gas-separating membranes. Selectivity and separation efficiency of PU-centered membranes are enhanced through modifications such as blending with other polymers, use of nanoparticles (silica, metal oxides, alumina, zeolite), and interpenetrating polymer networks (IPNs) formation. This manuscript critically analyzes the various gas transport methods and selection criteria for the fabrication of PU membranes. It also covers the challenges facing the development of PU-membrane-based separation procedures.

The prospect of synthesis of PES/PEG blend membranes using blend NMP/DMF for CO2/N2 separation

Carbon dioxide (CO2) emissions have been the root cause for anthropogenic climate change. Decarbonisation strategies, particularly carbon capture and storage (CCS) are crucial for mitigating the risk of global warming. Among all current CO2 separation technologies, membrane separation has the biggest potential for CCS as it is inexpensive, highly efficient, and simple to operate. Polymeric membranes are the preferred choice for the gas separation industry due to simpler methods of fabrication and lower costs compared to inorganic or mixed matrix membranes (MMMs). However, plasticisation and upper-bound trade-off between selectivity and permeability has limited the gas separation performance of polymeric membranes. Recently, researchers have found that the blending of glassy and rubbery polymers can effectively minimise trade-off between selectivity and permeability. Glassy poly(ethersulfone) (PES) and rubbery poly(ethylene) glycol (PEG) are polymers that are known to have a high affinity towards CO2. In this paper, PEG and PES are reviewed as potential polymer blend that can yield a final membrane with high CO2 permeance and CO2/nitrogen (N2) selectivity. Gas separation properties can be enhanced by using different solvents in the phase-inversion process. N-Methyl-2-Pyrrolidone (NMP) and Dimethylformamide (DMF) are common industrial solvents used for membrane fabrication. Both NMP and DMF are reviewed as prospective solvent blend that can improve the morphology and separation properties of PES/PEG blend membranes due to their effects on the membrane structure which increases permeation as well as selectivity. Thus, a PES/PEG blend polymeric membrane fabricated using NMP and DMF solvents is believed to be a major prospect for CO2/N2 gas separation.