Membrane-based Polymers of Intrinsic Microporosity (PIMs) are promising candidates for energy-efficient industrial gas separations, especially for the separation of carbon dioxide over methane (CO₂/CH₄) and carbon dioxide over nitrogen (CO₂/N₂) for natural gas/biogas upgrading and carbon capture from flue gases, respectively. Compared to other separation techniques, membrane separations offer potential energy and cost savings. Ultra-permeable PIM-based polymers are currently leading the trade-off between permeability and selectivity for gas separations, particularly in CO₂/CH₄ and CO₂/N₂. These membranes show a significant improvement in performance and fall within a linear correlation on benchmark Robeson plots, which are parallel to, but significantly above, the CO₂/CH₄ and CO₂/N₂ Robeson upper bounds. This improvement is expected to enhance the credibility of polymer membranes for CO₂ separations and stimulate further research in polymer science and applied engineering to develop membrane systems for these CO₂ separations, which are critical to energy and environmental sustainability. This review aims to highlight the state-of-the-art strategies employed to enhance gas separation performances in PIM-based membranes while also mitigating aging effects. These strategies include chemical post-modification, crosslinking, UV and thermal treatment of PIM, as well as the incorporation of nanofillers in the polymeric matrix.

A novel potentiometric sensor for carbon dioxide (CO₂) detection utilizing a composite membrane of Polymer of Intrinsic Microporosity (PIM‐1) and 18‐diazabicyclo[5.4.0]undec‐7‐ene imidazolate (DBU‐imidazolate) is presented. The high surface area and gas permeability of PIM‐1, combined with the chemical affinity and ion‐exchange properties of DBU‐imidazolate, contribute to enhanced CO₂ sensitivity and selectivity. The research objectives included the synthesis of PIM‐1 and DBU‐imidazolate, the preparation of composite membranes, and the evaluation of their performance as CO₂ sensors. Solvent casting and impregnation methods are employed to prepare the membranes, which are characterized using Thermal Gravimetric Analysis (TGA), and Field Emission Scanning Electron Microscopy (FESEM). CO₂ absorption tests and Electrochemical Impedance Spectroscopy (EIS) are conducted to assess the sensors' performance. The PIM‐1/DBU‐imidazolate membrane exhibited high efficiency in CO₂ capture and release. Open circuit voltage (OCV) measurements are performed under varying concentrations of CO₂ exposure and cycles of adsorption/desorption. Results show that the membrane achieves steady state faster at higher CO₂ concentrations, with a logarithmic relationship between CO₂ concentration and voltage variation, indicating potential for CO₂ detection in human environments. These results confirm the sensor's ability to detect varying CO₂ concentrations, highlighting its potential for reliable and efficient CO₂ monitoring in environmental and industrial applications.

The utilization of hydrogen in safety conditions is crucial for the development of a hydrogen-based economy. Among all methodologies, solid-state hydrogen release from ammonia borane through thermal stimuli is very promising due to the high theoretical hydrogen release. Generally, carbonaceous or inorganic matrices have been used to tune the reactivity of ammonia borane. Nevertheless, these solutions lack chemical tunability, and they do not allow one to properly tune the complex chemical pathway of hydrogen release from ammonia borane. In this study, we investigated the effect of a bioderived multifunctional polymeric matrix on hydrogen release from ammonia borane, reaching pure hydrogen release of 1.2 wt.% at 94 °C. We also describe new chemical pathways involving the formation of anchored intermediates, namely BxNy species.

The European Union has identified fluorite (CaF ₂ ) as a critical raw material (CRM) due to its economic importance, negligible recycling, and high import dependency. This study investigates a functionalized graphene oxide (fGO) membrane for purifying wastewater containing dissolved fluorides below the solubility limit of CaF ₂ and the subsequent CRM recovery. While the fundamental interaction is known in batch systems, closed‐loop recovery processes using this kind of membrane remain unexplored. Utilizing fGO synthesized via a scalable, green approach, we transition beyond conventional adsorption to a dynamic membrane‐stripping cycle. Comprehensive material characterization is provided. The fGO membranes were tested in a real‐case scenario using cleanroom facility wastewater. Fluorine concentration was successfully reduced from 21 down to 1.4 mg L ⁻¹ , meeting the EU/USA discharge and drinking water standards. High‐purity CaF ₂ powder was recovered. This work establishes a viable, non‐conventional membrane‐based approach for waste valorization, advancing circular economy principles in the semiconductor and microelectronics industries by transforming a hazardous waste into a strategic resource.