Characterization of Layer-by-Layer assembled graphene-based membranes for hydrogen purification

Hydrogen is increasingly examined as a valuable resource and energy carrier. However, current methods of its production are based on fossil fuels, resulting in carbon emissions and further climate change due to global warming. To solve these issues, multiple carbon capture methods are studied, with one of the options being based on membranes. Membranes in such systems are permeable but selective barriers that allow to efficiently extract hydrogen from gaseous mixtures. Polymeric selective barriers are made of polymers and stand out because of their large diversity. In practice, polyimide (e.g. Matrimid) and similar polymeric materials are utilized in membranes fabrication. As of today, they are constrained by an empirical limit (the Robeson upper bound), which states that selectivity declines with the increase in permeability. To overcome such a limitation, mixed matrix membranes have been introduced. In these systems, a polymeric material is incorporated or coated with organic or inorganic fillers. This approach is investigated in this work focused on the development of Grephene based mixed matrix membranes. In particular to maximize effect of graphenic fillers, this work considers multilayered coated membranes with the use of atomic-thick sheets of graphene oxide. Specifically, multilayered coatings of GO are deposited on a polyimide support, Matrimid, using the Layer by Layer technique. Permeation tests have been then performed to investigate the impact of the number deposited of layers on permselectivity performances of the developed membranes. Given the various factors influencing the LbL assembly, efforts have been made to standardize the procedure, aiming to enhance reproducibility and scalability. Overall, GO nanocomposite membranes demonstrate high effectiveness in hydrogen separation, providing valuable insights and potential for application in competitive systems.