Global lithium production currently relies on hard rock ores and high-grade brines, although these resources are insufficient to cover the rapidly increasing demand derived from electrification of multiple transportation and industrial sectors and all associated extraction processes generate important enrivonmental impacts. To address this gap and promote a circular economy for this metal, attention is turning to non-conventional sources, including low-grade brines, geothermal fluids, seawater, and industrial or battery recycling. Lithium-ion battery recycling is particularly relevant, as it allows recovery of lithium along with other valuable metals such as cobalt, nickel, and manganese. Conventional processes for lithium recovery, typically yielding lithium carbonate, often require very high temperatures or the use of multiple chemicals. However, this work focuses on the combination of leaching and nanofiltration (NF) techniques as a feasible and more eco-friendly approach to selectively recover lithium from multi-ionic liquors. Different acids and operating conditions were tested for the leaching stage, finding that citric acid exhibited a promising extraction performance while maintaining a suitable pH for subsequent membrane operation. Cross-flow NF was carried out by using a commercial polymeric membrane tested under different transmembrane pressures and pH values. Conditions that ensure a positive zeta potential were found to improve lithium rejection and, consequently, its recovery. Within the lab-scale NF framework, lithium recovery and pH-dependent permeate/retentate compositions are quantified, establishing clear process indicators aligned with the objectives of EU Regulation 2023/1542 and providing a concise data template readily adaptable to Battery Passport reporting.

The development of high-performance polymeric membranes is critical for advancing energy-efficient CO2 separation technologies. While machine learning (ML) has emerged as a powerful tool for predicting gas permeability and accelerating polymer discovery, most existing approaches rely on limited experimental descriptors and act as black boxes, offering little physical insight or reliability assessment. Here, we use ML as a molecular microscope to construct a physically informed and interpretable framework for predicting gas-transport properties in polymeric membranes for CO2 capture. By integrating structural fingerprints, physicochemical descriptors, and operational variables such as temperature and pressure, the framework moves beyond the typical black-box paradigm toward physically interpretable structure-property relationships. The approach combines data imputation through Multiple Imputation by Chained Equations (MICE), regression modeling with ensemble algorithms, and rigorous applicability-domain analysis to ensure predictive reliability. Feature-importance and explainability analyses reveal the molecular signatures that control gas transport—rigid, branched, and moderately polar architectures that balance free volume and solubility. This interpretive capability transforms ML into an analytical tool for rational polymer design, bridging predictive accuracy with chemical understanding and providing quantitative guidance for the next generation of CO2-selective membranes.

The development of high-performance anion exchange membranes (AEMs) is essential for advanced electrochemical technologies such as alkaline fuel cells and water electrolysis. Here, we investigate the influence of phosphonium side chain length on structural hydration and chloride ion transport in polymerized ionic liquid (MPIL) membranes. Atomistic molecular dynamics simulations are conducted on hydrated MPIL systems with ethyl, butyl, and octyl n-alkyl substituents, and simulation results are validated against experimental data for water uptake and ionic conductivity. Shorter side chains (ethyl) significantly enhance water uptake (approximate to 81 wt%) and promote the formation of interconnected hydrophilic channels, resulting in markedly higher Cl- ionic conductivity. In contrast, longer chains (octyl) restrict water accessibility and confine ion diffusion within localized hydrophilic domains, favoring ion retention tendency at the expense of transport efficiency. Intermediate chain length (butyl) yields a balanced morphology, combining moderate hydration with controllable ion mobility. Quantitative analyses, including pore connectivity descriptors, ion-ion association free energies from RDF integration, and backbone-water interaction profiles, consistently confirm that steric hindrance modulates hy-dration shell formation, ion pairing, and channel percolation. This molecular-level insight suggests that alkyl chain engineering provides a tunable parameter for optimizing trade-offs between ion conductivity and relative mobility control in MPIL-based AEMs. The combined computational and experimental results provide practical guidelines for designing next-generation membranes for desalination, electrochemical conversion, and energy storage.

A multiscale simulation framework combining density functional theory (DFT), grand canonical Monte Carlo (GCMC), and molecular dynamics (MD) was developed to elucidate CO2 and O-2 transport in amino-functionalized UiO-66/PDMS mixed matrix membranes (MMMs) relevant to extracorporeal membrane oxygenation (ECMO). The study systematically quantifies how MOF loading, crystallite size, and dispersion state influence gas adsorption, diffusion, and overall permeability. The results reveal a continuous transition of molecular motion from free diffusion in pristine PDMS to increasingly confined transport in amino-functionalized composites, governed by polymer densification and interfacial adsorption. At moderate loading (similar to 10 wt%), a balance between enhanced CO2 sorption and reduced diffusivity yields the maximum permeability, whereas higher filler contents or excessive aggregation hinder gas transport by disrupting percolation pathways. For O-2, weaker adsorption results in discontinuous, intermittently trapped diffusion and lower mobility. The simulated CO2 permeability (similar to 99 Barrer at 10 wt%) under ideal, defect-free, and dry conditions serves as a theoretical lower estimate compared with experimental values (similar to 1770 Barrer). Although the model does not reproduce ECMO operating conditions such as high humidity and physiological temperature, the mechanistic insights obtained here provide a molecular-level rationale for optimizing membrane materials for efficient and selective CO2 removal in biomedical gas-exchange systems.

Membrane distillation-crystallization (MD-MCr) has emerged as a promising route for recovering valuable salts and water from brine and wastewater streams; however, its industrial implementation depends critically on membrane robustness, scalability, and material chemistry, which together govern process selectivity and durability. Here, we employ constant chemical potential molecular dynamics (CμMD) simulations to probe the interfacial behavior of LiCl solutions in contact with polyvinylidene fluoride (PVDF) and polypropylene (PP) membranes across a range of concentrations. Concentration profiles reveal pronounced ion structuring near both polymer surfaces. PVDF exhibits gradual ion accumulation with increasing concentration, whereas PP displays distinct adsorption peaks only at higher salinity. Despite the absence of preferential ion adsorption and the resulting near-neutral interfacial charge distribution, adsorption isotherms and free-energy profiles reveal stronger affinity and greater interfacial heterogeneity for PVDF, arising from its polar fluorine groups. The deeper adsorption free-energy minima observed for PVDF indicate stronger ion-polymer interactions, consistent with the experimentally observed tendency of fluoropolymers to undergo wetting and structural modification upon prolonged exposure to lithium salts. These simulations, therefore, capture the earliest molecular-scale processes preceding membrane degradation. By linking polymer polarity, ion adsorption, and interfacial structuring, this work provides a molecular framework for understanding and tailoring ion-polymer interactions in membranes designed for lithium recovery and high-salinity separations.

Sustainable recovery of critical raw materials is essential for a circular economy. Lithium fluoride (LiF), a key component in lithium-ion battery production, is usually recovered through energy-intensive methods. This study introduces a greener alternative using membrane-assisted crystallization with hydrophobic polypropylene membranes. By combining molecular dynamics simulations and experimental analysis, we investigated the effects of temperature (300-353 K) and concentration (5.8-8.9 M) on LiF crystallization from aqueous solutions. Simulations revealed that polypropylene (PP) membranes delay nucleation (e.g., induction time increases from 8.5 ns to 18.5 ns at 300 K) mainly by reducing local supersaturation and significantly restricting ion diffusion, up to 86 % for Li+ at 300 K. These effects lower nucleation rates and promote more ordered crystal growth. The optimal crystallization dynamics were observed at 5.8 M and 353 K, with activation energies of 36.7 kJ mol- 1 for nucleation and 32.7 kJ mol- 1 for growth. Experimental results confirmed the delayed onset and enhanced crystal regularity in membrane-assisted systems. Overall, the use of PP membranes enables spatial control of supersaturation and crystal formation without chemical additives or solvent loss. This membrane-assisted pathway offers a scalable, low-energy strategy for selective lithium recovery from concentrated waste solutions.

Efficient and selective gas transport across soft and nonporous interfaces remains a pivotal challenge for biomimetic membrane design, particularly in extracorporeal membrane oxygenation (ECMO) systems. Here, we report a molecular-level mechanism by which interfacial confinement and protein assembly cooperatively induce CO2 selective transport in EAS (a class I hydrophobin that forms functional amyloid fibrils)-modified poly(4-methyl-1-pentene) (PMP) membranes. By using all-atom molecular dynamics simulations combined with potential of mean force (PMF) analysis, we systematically investigate gas permeation across EAS hydrophobin monomers, dimers, and trimers adsorbed on pristine and hydroxylated PMP surfaces. We find that oligomerization of EAS proteins drives the formation of interconnected interfacial cavities, transforming isolated transport pathways into a percolated pathway network. This structural transition reshapes the free-energy landscape from a barrier-dominated profile to a multi-well topology. CO2 can be selectively stabilized along the permeation coordinate, while O2 transport remains governed by higher and more localized barriers. Importantly, surface hydroxylation further amplifies this effect by introducing polar interactions that act as a tunable parameter for modulating interfacial energetics and gas-protein coupling. These findings establish an interfacial confinement-induced transport mechanism in which gas selectivity emerges not from intrinsic pore size, but from the collective interplay of protein assembly, interfacial free volume, and molecular interactions. This work provides a general design principle for engineering bioinspired composite membranes with enhanced gas selectivity in ECMO and related gas-separation applications.

The increasing demand for lithium in lithium-based batteries (LIBs) underscores the urgent need for sustainable recovery technologies, particularly for recycling exhausted batteries. Membrane-assisted crystallization (MCr) has emerged as a promising method for lithium recovery, enabling the production of high-quality crystals with minimal environmental impact. Although MCr has been widely explored across various applications, its specific role in the crystallization of lithium salts—especially lithium fluoride (LiF)—remains under-researched. This study examines the interactions between LiF solutions and polypropylene (PP) membranes during the crystallization process through molecular dynamics (MD) simulations. By comparing systems with membrane, from now on referring simply as Membrane, and without the membrane, from now on referring with the word Bulk, we highlight the membrane's pivotal role in influencing water and ion diffusion, promoting ion aggregation, and enhancing crystal formation. The results demonstrate that PP membranes slow water diffusion while facilitating ion mobility, leading to the development of more ordered and crystalline structures. Additionally, interactions with the ionic solution induce subtle morphological changes in the membrane, which influence the spatial arrangement of forming crystals. Experimental validation supports these findings, showing that PP membranes significantly improve crystal quality and structure. This work underscores the essential role of PP membranes in advancing sustainable and efficient lithium recovery technologies.

Understanding the early-stage physical interactions between polymeric membranes and supersaturated salt solutions is crucial for advancing membrane-assisted crystallization (MCr) processes. In this study, we employed molecular dynamics (MD) simulations to investigate the short-term morphological response of an isotactic polypropylene (PP) membrane in contact with LiF solutions at different concentrations (5.8 M and 8.9 M) and temperatures (300–353 K), across multiple time points (0, 150, and 300 ns). These data were used as input for computational fluid dynamics (CFD) analysis to evaluate structural descriptors of the membrane, including tortuosity, connectivity, void fraction, anisotropy, and deviatoric anisotropy, under varying thermodynamic conditions. The results show subtle but consistent rearrangements of polymer chains upon exposure to the hypersaline environment, with a marked reduction in anisotropy and connectivity, indicating a more compact and isotropic local structure. Surface charge density analyses further suggest a temperature- and concentration-dependent modulation of chain mobility and terminal group orientation at the membrane–solution interface. Despite localized rearrangements, the membrane consistently maintains a net negative surface charge. This electrostatic feature may influence ion–membrane interactions during the crystallization process. While these non-reactive, short-timescale simulations do not capture long-term degradation or fouling mechanisms, they provide mechanistic insight into the initial physical response of PP membranes under MCr-relevant conditions. This study lays a computational foundation for future investigations bridging atomistic modeling and membrane performance in real-world applications.

The escalating demand for lithium, driven by its pivotal role in electronic devices and lithium-ion batteries, underscores the urgent need for sustainable lithium recovery methods. Recycling lithium from spent batteries represents a promising strategy to meet this demand; however, a detailed understanding of crystallization processes in the presence of functional interfaces remains largely unexplored. In this study, we present a novel investigation into the role of polypropylene (PP) membranes in controlling the crystallization dynamics of lithium fluoride (LiF) from ionic solutions. Using a combined computational and experimental approach, molecular dynamics (MD) simulations are performed to compare bulk crystallization with crystallization occurring at the membrane interface. Our results reveal that the membrane deeply influences the crystallization process, increasing induction times and reducing nucleation and growth rates, which indicates a more controlled and structured crystal formation. Notably, the presence of the membrane enhances the crystallinity of the formed crystals, likely due to its structuring effect on the surrounding ionic environment. To assess the impact of the ionic solution on the membrane, we further analyzed morphological parameters and conducted experimental validation. The polypropylene membrane demonstrated exceptional robustness, retaining its structural stability and hydrophobicity, as confirmed by contact angle measurements, even after prolonged exposure to the solution. Experimental trends in nucleation times, crystal morphology, and membrane behavior align closely with the computational findings, reinforcing the reliability of our results. This study introduces a novel perspective on the interactions between membranes and crystallizing ionic systems, providing fundamental insights into the role of membrane interfaces in influencing crystallization dynamics. The findings pave the way for optimized membrane-based processes, offering valuable knowledge to advance sustainable lithium recovery technologies.

Hollow fiber membranes have revolutionized various gas separation processes due to their unique characteristics such as high surface area, small system footprint, and high energy efficiency compared to flat sheet or spiral wound membranes. This review analyzes the current state of the art of hollow fiber technology, exploring its diverse applications across various fields. Over the past ten years, research has primarily focused on improving hollow fiber fabrication techniques, including phase inversion, electrospinning, and 3D printing, highlighting their impact on membrane performance and selectivity. Furthermore, we discuss the challenges and future perspectives of hollow fiber technology, focusing on the development of novel materials and surface modifications to enhance membrane durability and efficiency. Finally, this review provides an overview of current gas separation techniques, spanning both conventional and next-generation methods, based on the foreseen field of exploitation of hollow fiber membranes.

Previously, it has been reported that amine-PIM-1, a polymer of intrinsic microporosity obtained by reduction of nitrile groups of PIM-1 to primary amine groups, shows enhanced CO2 selectivity during mixed gas permeation studies with respect to single gas measurements for gas pairs involving CO2. This distinct and potentially useful behaviour was ascribed to the affinity of CO2 for the polymer amine groups. Here, we demonstrate that enhanced selectivity originates from both CO2 physisorption and chemisorption. A combination of 13C and 15N solid-state NMR spectroscopic analyses of a CO2-loaded amine-PIM-1 membrane allowed the identification and quantitative determination of both chemisorbed and physisorbed species and the characterization of polymer-CO2 interactions. Experiments with 13C isotopically enriched CO2 unequivocally demonstrated the conversion of 20% of the NH2 groups into carbamic acids at 298 K and a CO2 pressure of 1 bar. Chemisorption was supported by the strong heat of CO2 adsorption for amine-PIM-1 that was estimated as 50 kJ mol-1. Molecular dynamics simulations with models based on the experimentally determined polymer structure gave a detailed description of intra- and interchain hydrogen bond interactions in amine-PIM-1 after chemisorption, as well as of the effect of chemisorption on polymer porosity and physisorption.

We present the results of a computational investigation of the structure and distribution of pore size in a polymer of intrinsic microporosity (PIM), a class of compounds with applications as sensors and membranes for gas separation. The high performance of PIMs, in our case PIM-EA-TB, meaning a PIM based on ethanoanthracene (EA) units linked by a Tröger's base (TB, i.e., methanodiazocene), is largely due to the presence of interconnected micropores within the rigid polymer matrix. We have applied a computational NMR protocol based on a combination of MD simulations to generate several trajectories of xenon within the polymeric matrix and DFT calculations of the 129Xe chemical shift using clusters extracted from the MD trajectories. The comparison of experimental NMR data previously obtained and the results of the calculations allows to validate the bulk structure resulting from the MD simulations and to obtain a quantitative dependence of the 129Xe chemical shift on the distance of xenon from the pores' internal walls. Such dependence is in very good agreement with the results reported in the literature concerning small model systems of Xe-alkane pairs and hints at a more general law that can be expected to hold for many different systems.

Triazole-functionalized graphene oxide (Tz@GO) nanosheets were incorporated into an EXTEM (R) XH 1015 polyetherimide to fabricate mixed matrix membranes (MMMs). Tz@GO was synthesized through a simple threestep click chemistry approach. The physicochemical properties of the EXTEM (R) polymer membranes were analysed before and after Tz@GO incorporation using various analytical techniques. Cross-sectional morphology analysis of the MMMs demonstrated a well-integrated polymer-nanofiller interface, indicating homogeneous dispersion of Tz@GO and the EXTEM (R) matrix. Mechanical testing confirmed that Tz@GO reinforcement significantly enhanced the mechanical properties of the membranes. A comprehensive investigation carried out into MMMs' gas transport abilities revealed that Tz@GO incorporation effectively improved gas permeability. This enhancement is attributed to Tz@GO's ability to inhibit polymer chain entanglement, thereby increasing fractional free volume (FFV). The highest gas permeability was observed at a Tz@GO loading of 0.8 wt%. This study presents an innovative approach by maintaining the improved mechanical properties and CO2 separation performances of Tz@GO-incorporated EXTEM (R) membranes for CO2 capture application.

The recovery of lithium from extracts obtained from a black mass of spent lithium-ion batteries treated with a ternary solvent system at acidic pH was investigated using flat-sheet nanofiltration (NF) membranes operated according to a dead-end configuration. Specifically, four samples obtained at different pH values (2.5 and 5) and extraction times (48, 96 and 168 h) were treated in selected operating conditions by using two commercial polymeric membranes (denoted DK and HL, with an approximate molecular weight cut-off of 150–300 Da) up to a volume reduction factor (VRF) of 4. Membrane performance was assessed in terms of productivity and selectivity towards specific ions, including lithium. For most treated samples, the HL membrane exhibited higher permeate fluxes in comparison to the DK membrane. However, the DK membrane performed better in terms of lithium rejection than the HL membrane, with a negative rejection at VRF 4 observed for all treated samples. More than 90% of multivalent ions were rejected by both membranes independently of the VRF. The membrane ability to retain multivalent ions led to their progressive concentration in the retentate as the VRF increased. The extraction time did not impact the NF performance of both membranes in terms of ion rejection. For the DK membrane conditions of extraction of 96 h and pH 5 represented the best trade-off between flux, ion rejection, and total lithium recovery.

HYPOTHESIS:Crystal properties are essential in determining the functionality of final products in pharmaceutical and food applications. This study hypothesizes that membrane-assisted antisolvent crystallization (MAAC) can regulate supersaturation profiles to influence polymorph selection and crystal growth kinetics in glycine crystallization. By using polyvinylidene fluoride (PVDF) membranes to control ethanol diffusion, it is expected that MAAC can promote the formation of specific polymorphs, particularly α-glycine, through modulation of molecular self-assembly pathways. EXPERIMENTS:To test this hypothesis, MAAC was implemented with PVDF membranes to generate stable supersaturation conditions during glycine crystallization. The membrane served as a mass transfer barrier, enabling controlled ethanol diffusion and allowing for detailed analysis of crystal size and polymorphic distribution. Experimental crystallization outcomes were complemented by molecular dynamics (MD) simulations of glycine-water-ethanol systems at three supersaturation levels (S = 0.74, 1.35, and 2.39). These simulations were used to investigate the formation of molecular aggregates and hydrogen bonding patterns, and to quantify nucleation induction times under varying supersaturation conditions. FINDINGS:MAAC enabled the formation of α-glycine with a narrow chord length distribution and a mean size of 86 μm. MD simulations revealed that cyclic glycine dimers, precursors to α-glycine, formed at lower supersaturation, while disordered aggregates associated with β-glycine dominated at higher supersaturation. Ethanol was shown to modulate hydrogen bonding and self-assembly, influencing polymorphic outcomes. Induction times decreased significantly with increasing supersaturation, from 1.9 ns to less than 100 ps, highlighting the kinetic control enabled by membrane-regulated crystallization.

Heterogeneous catalysis is significantly enhanced by the use of highly porous polymers with specific functionalities, such as basic groups, which accelerate reaction rates. Polymers of intrinsic microporosity (PIMs) provide a unique platform for catalytic reactions owing to their high surface areas and customizable pore structures. We herein report a series of Troger's base polymers (TB-PIMs) with enhanced basicity, achieved through the incorporation of nitrogen-containing groups into their repeat units, such as triazine and triphenylamine. These polymers offer a perfect balance between the pore "swellability", which allows the use of substrates of various dimensions, and the basicity of their repeat units, which facilitates the use of reactants with diverse acidity. The catalytic activity is evaluated through the Knoevenagel condensation of benzaldehydes and various methylene species, conducted in the presence of ethanol as a green solvent and using a 1:1 ratio of the two reagents. The results highlight a significant improvement, with reactions reaching completion using just a 1% molar ratio of catalysts and achieving a 3-fold enhancement over previous results with 4-tert-butyl-benzaldehyde. Computational modeling confirms that the enhanced basicity of the repeat units is attributable to the polymer design. Additionally, preliminary studies are undertaken to assess the kinetics of the catalyzed condensation reaction.

Engineering the properties of the membrane system has become a fundamental goal to achieve a membrane with an optimal structure and pore size distribution. Several parameters such as contact phase, composition of phases, polymer solution temperature, and nonsolvent/solvent species must be controlled to achieve this goal. Due to the multiplicity of process variables, the complexity of the interactions, as well as the speed of the process, it is difficult to determine and observe the PI process only through laboratory techniques. Modeling the phase separation process and developing efficient numerical models capable of predicting the final membrane morphology as accurately as possible, depending on the wide range of parameters. In this chapter, two top-down approaches—macroscopic transport models and mesoscopic PF models—as well as bottom-up molecular/particle scale simulations (such as molecular dynamics [MD], Monte Carlo and dissipative particle dynamics [DPD]), are presented to describe the processes of phase inversion, transfer phenomena, and membrane formation. Furthermore, a comprehensive view of the development of models over time and the presentation of numerical results from different models was provided to readers as a key solution for better understanding the limitations and capabilities of the simulations. Additionally, the use of machine learning as a robust tool for predicting membrane performance prior to fabrication is discussed.

The condensation of water vapor plays a crucial role in various applications, including combating water scarcity. In this study, by employing molecular dynamics simulations, we delved into the impact of graphene coatings on water vapor condensation on copper surfaces. Unique to this work was the exploration of various levels of graphene coverage and distribution, a facet largely unexplored in prior investigations. The findings demonstrated a notable increase in the rate of water vapor condensation and heat transfer performance as the graphene coverage was reduced. Using graphene coverages of 84%, 68%, and 52%, the numbers of condensed water molecules were 664, 735, and 880 molecules/ns, respectively. One of the most important findings was that when using the same graphene coverage of 68%, the rate of water vapor condensation and heat transfer performance increased as the graphene coating became more distributed. The overall performance of the water condensation correlated well with the energy and vibrational interaction between the graphene and the copper. This phenomenon suggests how a hybrid surface can enhance the nucleation and growth of a droplet, which might be beneficial for tailoring graphene-coated copper surfaces for applications demanding efficient water vapor condensation.

The combination of perfluoropolymers with perfluorinated metal-organic frameworks (MOFs) can play an important part in the development of mixed-matrix membranes (MMMs) for the capture of CO2, thanks to the enhanced selectivity toward CO2 and resistance to humidity. Herein, we report the incorporation of the perfluorinated nanoporous MOF F4_MIL-140A(Ce), based on Ce-IV and tetrafluoroterephthalate, into one of the most representative perfluoropolymers in membrane science, i.e., Hyflon (R) AD60X, to form a MMM containing 20 wt % of the MOF filler for the separation of CO2 from N-2 and CH4. The membrane was characterized by solid-state nuclear magnetic resonance (NMR) spectroscopy, infrared spectroscopy (IR), and gas sorption analysis, finding that the MOF retains its peculiar cooperative mechanism of CO2 adsorption even when embedded in the polymeric matrix. Pure-gas permeation tests on the MMM confirmed the enhancement of selectivity for CO2/N-2 and CO2/CH4 gas mixtures, with nonvirtual reduction in permeability. The incorporation of F4_MIL-140A(Ce) into Hyflon (R) AD60X enhances the CO2/CH4 selectivity from 9.1 to 14.3 and from 6.2 to 7.7 for CO2/N-2 separation. The CO2 permeabilities are slightly reduced by less than 5% from 304 to 290 Barrer. Adsorption isotherms, combined with IR and solid-state NMR spectroscopy measurements, suggested that the MMM behavior can be ascribed to the peculiar CO2 adsorption mechanism of F4_MIL-140A(Ce), which is retained even when the MOF is embedded in the polymer matrix.