Abstract Membrane technologies have made critical advances in resource recovery, water purification, and energy systems. However, it is difficult to systematically tune properties of traditional polymer membranes, and researchers have struggled to deliver challenging, advanced separations using these platforms. In recent years, membranes based on 2D materials have drawn attention for molecular‐scale separations due to their unique properties, most notably their tunable nanoscale interlayer properties. Among the diverse family of 2D materials, phyllosilicates, a broad class of naturally abundant clay minerals, offer significant advantages in cost and scalability over synthetic 2D materials, positioning them as promising candidates for advanced membrane technologies. Their inherent structural and chemical properties, strategies for tailoring selective transport pathways, and recent advancements across applications including ion separation, water treatment, and energy conversion are discussed. Finally, key challenges and opportunities are outlined to guide future research in leveraging phyllosilicate membranes for high‐performance separation technologies.

Neuromorphic ionic computing is inspired by the brain's use of ions for ultralow-energy computation-its massive parallelism, adaptability, and learning capabilities. This emerging paradigm can overcome limitations of conventional silicon-based computing by enabling colocated memory and processing, multicarrier information streams, and massive three-dimensional connectivity. However, substantial knowledge gaps remain in understanding and engineering ionic transport, energy dissipation, materials design, and scalable device architectures. This Review explores these critical challenges across seven key domains, highlighting the need for new theoretical approaches, materials, device concepts, and fabrication strategies. We argue that advancing ionic neuromorphic systems requires an interdisciplinary approach, integrating insights from biology and neuroscience, nanofluidics, materials science, and systems engineering to enable a new class of energy-efficient, robust, and reconfigurable computing technologies.

The U.S. Department of Energy (DOE) national laboratories represent a unique class of government-owned, contractor-operated research institutions dedicated to conducting research and development (R&D) related activities that address national priorities, supporting and advancing the DOE mission. They play a vital role in sustaining U.S. innovation capacity, stewarding the nation's technical base, and nurturing science and technologies. In this perspective, we highlight the processing science and scaleup capabilities of the Materials Engineering Research Facility (MERF) at DOE's Argonne National Laboratory to demonstrate how DOE National Laboratories bridge fundamental science and applied technology development to accelerate deployment. Case studies are presented on selective membranes for critical mineral recovery, sensors for per- and polyfluoroalkyl substances (PFAS) detection, surface functionalization via atomic layer deposition (ALD) and sequential infiltration synthesis (SIS), and lithium recovery from battery recycling waste streams using a novel electrodialysis process. These examples underscore MERF's role in translating innovative technologies into practical solutions for renewable water and critical resource recovery, which also leverage Argonne's analytical and computational capabilities. This perspective also outlines mechanisms for collaborating with the DOE national laboratories to strengthen partnerships across government, the national laboratories, academia, and industry.

Per-and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that demand highly sensitive and selective molecular recognition strategies for field-deployable detection. Cyclodextrin-based field-effect transistor (FET) sensors demonstrate high sensitivity to perfluorooctanesulfonic acid (PFOS), achieving sub-ppt detection limits, yet exhibit limited selectivity in the presence of structurally similar surfactants such as sodium dodecyl sulfate (SDS). In this work, we integrate molecular docking, all-atom molecular dynamics free energy calculations, and Bayesian optimization to computationally evaluate the competitive binding thermodynamics of a synthetic library of 1,629 functionalized α-, β-, and γ-cyclodextrins. Our screen identifies highly sensitive PFOS probes with predicted dissociation constants as low as K d PFOS = 2.8×10 −11 M and highly selective probes with PFOS selectivities over SDS of up to K d SDS /K d PFOS = 1.5×10 5 , corresponding to a 6,000× improvement in sensitivity and 2,500× improvement in selectivity over unfunctionalized β-cyclodextrin. Amine-functionalized cyclodextrins yield the highest discrimination ratios by selectively suppressing SDS binding under competitive conditions, while fluorinated groups further enhance PFOS selectivity through favorable host-guest interactions. Regression analysis reveals that PFOS affinity correlates with hydrophobic surface area, whereas high selectivity additionally depends on charge-resolved and electronic descriptors. These results establish quantitative structure-selectivity relationships for cyclodextrin-based PFOS recognition and provide design principles for next-generation PFAS molecular sensors.

Two-dimensional (2D) materials are physical building blocks of laminar membranes with interlayer channels for ion and molecular transport. Here, we systematically investigate the influence of lateral sheet size on the ion permeability and structural organization of vermiculite membranes. We show that the sheet size plays a significant role in governing the microstructure of these laminar systems. High resolution x-ray diffraction analysis reveals changes in mosaic distribution and vertical domain size depending upon exfoliate lateral size, leading to changes in the degree of polycrystallinity of the membrane. As these structural variations influence ion transport processes through the membrane, we highlight the need of careful size control of exfoliated 2D materials and structural disorder analysis for 2D laminar membrane development.

Abstract Interfacial solar evaporation has shown promise as an inexpensive method to produce potable water with limited infrastructure and to accelerate resource concentration processes. However, higher evaporation rates and more scalable evaporator designs are needed to achieve practical implementation. In this work, we assessed the integration of conical reflectors with three-dimensional evaporator materials to enhance light capture for boosted evaporation efficiency. Across varying geometric parameters, we observed multifold enhancements in the quantity of water evaporated but a decrease in the normalized evaporation rate due to the large projected area of the reflectors. Both of these phenomena correlated directly with the reflector angle and the exposed height of the evaporator, as wider and taller structures captured more light and offered greater surface area for evaporation. We explored how reflectors could be arranged in large-scale arrays for more efficient space utilization and suggest that the evaporation rate normalized to the active or projected area of a single evaporator may not be a suitable indicator of its potential performance at larger scales.

ABSTRACT Separating crude oil from water remains one of the most stubborn challenges in environmental remediation, especially for surfactant‐stabilized emulsions that resist conventional demulsification methods. Here, we report a scalable strategy for achieving near‐zero‐discharge separation of crude oil emulsions using a single superhydrophilic membrane. By applying low‐temperature atomic layer deposition (ALD) of various metal oxides onto activated polyvinylidene fluoride (PVDF) membranes, we create atomically precise surface‐engineered (SE) membranes that maintain an exceptionally strong hydration layer at the membrane‐feed interface, even at high oil loadings. Among the various metal oxides, TiO 2 ‐modified SE membranes exhibit superior interfacial water stability, enabling sustained dewatering of complex crude oil‐water emulsions with >98% separation efficiency and >97% water recovery, compared to only 24.6% water recovery for the pristine membrane. This separation performance surpasses conventional hydrophilic membranes and is comparable to complex Janus channel membrane systems, demonstrating near‐complete emulsion separation using a single membrane. This low‐temperature membrane surface engineering process with atomic‐level precision and potential for scalability via roll‐to‐roll fabrication is promising for industrial‐scale, energy‐efficient water treatment and oil spill remediation applications.

Rapid industrial growth has increased the need for efficient membranes to separate oil-water emulsions. Polyvinylidene fluoride (PVDF) membranes, although widely used due to their chemical inertness and favorable mechanical properties, suffer from fouling due to their intrinsic hydrophobicity. Modifying these membranes after fabrication offers a practical solution as it easily fits into existing large-scale manufacturing processes. Atomic layer deposition (ALD), an atomically-precise vapor phase surface modification technique, can create ultrathin metal oxide layers that greatly improve membrane hydrophilicity without significantly affecting the original pore size. However, PVDF's lack of reactive chemical moieties makes ALD challenging. Here, we present a simple alkali treatment that greatly enhances ALD nucleation and growth on PVDF membranes. This treatment imparts exceptional oil-water emulsion separation capabilities and antifouling behavior in PVDF membranes after just a few ALD cycles, surpassing the performance of PVDF membranes coated with hundreds of ALD cycles. This dramatic reduction in the number of ALD cycles required could enable cost-effective modification of commercial PVDF membranes at scale using spatial, roll-to-roll ALD. These modified membranes outperform reported modified PVDF membranes, with >99 % permeance recovery and <1 % irreversible loss of permeance and >98 % oil rejection from oil-water emulsions over 100 h continuous operation, making them promising for advanced water purification technologies.

The low Li + concentration and the abundance of competing ions limit the efficiency of lithium extraction from seawater. In this work, we report a solar-powered seesaw extractor (SPSE) to boost Li + adsorption while minimizing scaling caused by competing ions during photothermal evaporation. The SPSE features a sandwich architecture, with a hydrophilic adsorbent layer placed between two hydrophobic photothermal layers. The seesaw configuration enables Li + to be elevated and concentrated through evaporation to overcome sluggish adsorption kinetics, while the associated salt scaling is removed by the seesawing motion. As a demonstration, we assembled 60 SPSEs into a 3 & times; 20 array that achieved a 15.5-fold increase in local Li + concentration and a 69.1% improvement in Li + uptake over 120 h, with a Li + /Na+ separation factor exceeding 370,000.

Membrane technologies can enhance the efficiency and selectivity of chemical separations in energy-water systems. Advanced characterization tools are critical for discerning separation mechanisms, revealing degradation processes, and designing novel materials and material systems for new and emerging challenges. The pursuit of next-generation membranes for water and energy applications requires understanding phenomena at the molecular scale, mesoscale, and macroscale. This perspective highlights advanced characterization techniques for elucidating and enhancing membrane performance, while addressing fundamental trade-offs involved in characterizing membranes under realistic conditions.

Effective membrane separation of Li+ from Na+ and Mg2+ is crucial for lithium extraction from water yet challenging for conventional polymeric membranes. Two dimensional (2D) membranes with ordered laminar structures and tunable physicochemical properties offer distinctive ion-sieving capabilities promising for lithium extraction. Recently, phyllosilicates are introduced as abundant and cost-effective source materials for such membranes. However, their water instability and low inherent ion transport selectivity hinder practical applications. Herein, a new class of laminar membranes with excellent stability and tunable ion sieving is reported by incorporating inorganic alumina pillars into vermiculite interlayers. Crosslinking vermiculite flakes with alumina pillars significantly strengthens interlamellar interactions, resulting in robust water stability. Doping of Na+ before the pillaring process reverses the membrane's surface charge, substantially boosting Li+ separation from multivalent cations via electrostatic interactions. Lithium extraction is often complicated by the presence of co-existing monovalent cations (e.g., Na+) at higher concentrations. Here, by introducing excess Na+ into the membrane after the pillaring process, the separation of Li+ from monovalent cations is enhanced through steric effects. This work realizes both monovalent/multivalent and monovalent/monovalent selective ion sieving with the same membrane platform. A separation mechanism is proposed based on Donnan exclusion and size exclusion, providing new insights for membrane design for resource recovery applications.

The advent of AI and machine learning offers unprecedented potential to address global challenges, but it comes with an escalating demand for computing power and energy consumption. The need for energy-efficient computing mechanisms is more pressing than ever, and we can look to the brain for inspiration on co-localized computation and memory for highly efficient information processing. Emulating the brain in synthetic systems requires a deeper understanding of the ion transport mechanisms and device characteristics required to achieve this goal. Promising devices include memristors that integrate their history of applied currents and voltages to affect their future conductance in a process that mimics the propagation of signals across neurons via changes in synaptic strength. This research explores how asymmetrically charged nanochannels can be tuned to exhibit memristive neuromorphic plasticity. To achieve this, we will fabricate a device with charge-Janus properties through advanced lithography techniques and functional coatings. These charge asymmetries will be characterized and confirmed through x-ray photoelectron spectroscopy and zeta potential measurements, while current-voltage sweeps across varying electrolyte compositions and concentrations will probe the system’s memristive hysteresis. Voltage pulse sequences can be applied to evoke neuromorphic Hebbian learning, which could be integrated with a single-layer neural network to perform logic. Through this work, we will be able to uncover mechanisms of asymmetric ion transport in nanochannels to aid the development of energy-efficient, brain-inspired computing architectures, and it will also support advancements in chemical separation and sensing applications.

Widespread, persistent, and toxic per- and polyfluoroalkyl substances (PFAS) pose a major threat to both water systems and human health. Current PFAS detection methods are relatively expensive, slow, and complex. To combat PFAS contamination and meet increasingly stringent regulations of PFAS in drinking water, the development of highly sensitive and selective PFAS sensing techniques is urgently needed. Herein, we present an ultrasensitive sensing platform for perfluorooctane sulfonic acid (PFOS) detection in tap water with a reporting limit (~250 ppq) lower than the maximum contaminant level (4 ppt) set by the U.S. Environmental Protection Agency, using remote gate field-effect transistor (RGFET) sensors featuring β-cyclodextrin (β-CD)-modified reduced graphene oxide as the sensing membrane. The sensor exhibits excellent selectivity against common inorganic ions (e.g., Na+, K+, Ca2+, Cl-, HPO42-, SO42- ) and select organic pollutants (e.g., trichloroacetic acid) in tap water. Importantly, the reversible and rapid response (< 2 min) indicates the potential of RGFET for continuous inline monitoring of PFAS. Quartz crystal microbalance results emphasize the important roles of both analyte adsorption and charge properties of analytes and buffers in generating sensing signals. The binding nature between β-CD probe and PFOS or interferent molecules, as well as the spatially resolved selectivity revealed by molecular dynamics simulations, suggest rational probe engineering strategies for future selective capture probe design.

Fouling is a grand challenge which severely degrades membrane system performance, especially for applications in water treatment. Polyvinylidene fluoride (PVDF) is widely used for membrane fabrication due to its inertness and stability. However, PVDF is extremely susceptible to fouling due to its inherent hydrophobicity. Post-synthetic functionalization of PVDF membranes can increase the membrane-foulant interaction energy and reduce fouling. In this regard, vapor phase functionalization is particularly promising since it can produce ultrathin films (<5 nm) which do not alter the membrane pore structure and morphology. For example, thin metal oxide layers impart hydrophilicity and are often positively charged at the pH of the wastewater, realizing high membrane – foulant interaction energy. Atomic layer deposition (ALD) can produce ultrathin metal oxide layers on polymers, but the inert PVDF surface inhibits nucleation necessitating a prohibitively large number of ALD cycles to impart fouling resistance. In this presentation, I describe a novel pretreatment step that dramatically accelerates the nucleation of metal oxide ALD on PVDF. Using this pretreatment, we create highly effective anti-fouling surfaces using one ALD cycle compared to >150 ALD cycles on the pristine PVDF membranes. This strategy is effective for a range of ALD metal oxides including Al 2 O 3 , TiO 2 , and ZnO. We employ a suite of in situ and ex situ analytical techniques to elucidate the surface chemical mechanism for the enhanced nucleation. We perform extensive characterization and testing of the surface-engineered PVDF to quantify the benefits for water filtration and demonstrate >99% flux recovery with only ~1% irreversible flux loss during operation. We also demonstrate the efficacy of our surface engineered PVDF membranes for oil-water separation. Efforts are underway to perform this surface treatment using our roll-to-roll, atmospheric pressure spatial ALD system.

Research now demonstrates that solution-processable polymer membranes with hydrophilic subnanometre pores can selectively extract lithium ions from salt-lake brines, offering a potentially sustainable approach to meet the growing demand for lithium in energy storage applications.

Interfacial solar evaporation using three-dimensional evaporator materials has shown promise to achieve high evaporation rates exceeding the photothermal limit for water treatment and resource recovery processes. However, challenges remain in optimizing the material geometry to balance the vertical capillary uptake of water and the rate of evaporation to achieve both stable and high evaporation rates. Delignified wood can serve as a highly porous and hydrophilic substrate material to achieve high evaporation rates. In this work, we designed a suspended biochar-coated delignified wood rod evaporator and investigated the influence of its geometric parameters on its evaporation performance. The height of the evaporator exposed to air for evaporation was observed to be an important parameter in governing the evaporation rate, as shorter evaporators limited the available surface area for evaporation, but taller evaporators could not achieve sufficient rates of capillary uptake to maintain stable evaporation rates over 24 h under 1-sun illumination (1 kW m-2). The exposed height of the evaporator was optimized to achieve an average hourly evaporation rate of 3.05 ± 0.23 kg m-2 h-1, which could be maintained in saline solutions containing up to 5 wt % NaCl.

Janus configurations, characterized by their inherent asymmetry, enable directional mass transfer in membrane materials that drive novel and energy-efficient chemical processes. This Janus superiority spans applications from nanoscale molecular and ionic transport to macro-scale separation systems with asymmetric spatial architectures. This review provides an analysis of the material foundations including design principles, structure regulation, and scalability challenges underlying Janus membranes. We explore the physics that governs their unique behavior and examine their diverse applications across chemical engineering, including phase transfer, and molecular or ionic transport. Through a multiscale perspective, we provide a comprehensive understanding of the impact of Janus superiority in advancing chemical engineering technologies. Finally, we discuss the hurdles in translating theoretical advances into practical applications and propose promising avenues for future research to harness the full potential of Janus membranes and systems in addressing global challenges related to energy, sustainability, and beyond.

Atomic layer deposition (ALD) is a powerful strategy to engineer hybrid organic-inorganic membranes with emergent functionalities. The combination of atomic-level thickness control, wide materials palette, and unprecedented conformality allow the physiochemical properties (e.g., hydrophilicity) of mesoporous polymer membranes to be precisely tuned. The nucleation of ALD materials growth on polymer surfaces relies on chemical interactions between the ALD metalorganic precursor and functional groups in the polymer structure and these interactions dictate the number of ALD cycles required to achieve a continuous coating. Strategies to enhance these interactions could enable desirable properties such as anti-fouling behavior to be imparted on inert polymer surfaces that lack the necessary functional groups for ALD nucleation. In this study, we demonstrate that the reactivity of polyacrylonitrile (PAN) membranes towards ALD metal oxide (MO) precursors with Lewis acid characteristics is enhanced by introducing Lewis base functional groups (amidoxime: Am) on the PAN backbone. The resulting Lewis acid-base interactions accelerates the MO nucleation in Am-PAN and reduce the number of deposition cycles required to achieve hydrophilicity compared to the untreated PAN membrane. Unveiling the reaction mechanism, the in-situ FTIR intensity changes established enhanced interaction dynamics between the ALD MO precursors and the Am-PAN membrane, unlike the PAN membrane. For similar MO cycles, through both spectroscopic and thermogravimetric analysis, we observe enhanced MO loading in the Am-PAN membrane compared to the PAN membrane. Here we have verified that strong Lewis acid-base interactions led to enhanced loading for a range of ALD MO materials including Al2O3, TiO2, SnO2, and ZnO. Most importantly, the Al2O3-Am-PAN hybrid membrane showed 23.3% higher antifouling capability compared to the pristine PAN membrane. Our approach expands the scope of design options for fouling-resistant porous hybrid inorganic-organic membranes and may reduce manufacturing costs of water treatment membranes.

Water-energy sustainability will depend upon the rapid development of advanced pressure- driven separation membranes. Although energy- efficient, water- treatment membranes are constrained by ubiquitous fouling, which may be alleviated by engineering self- cleaning membrane interfaces. In this study, a metal- polyphenol network was designed to direct the armorization of catalytic nanofilms (ca. 18 nm) on inert polymeric membranes. The chelation- directed mineralized coating exhibits high polarity, superhydrophilicity, and ultralow adhesion to crude oil, enabling cyclable crude oil- in- water emulsion separation. The in- place flux recovery rate exceeded 99.9%, alleviating the need for traditional ex situ cleaning. The chelation- directed nanoarmored membrane exhibited 48- fold and 6.8- fold figures of merit for in- place self- cleaning regeneration compared to the control membrane and simple hydraulic cleaning, respectively. Precursor interaction mechanisms were identified by density functional theory calculations. Chelation- directed armorization offers promise for sustainable applications in catalysis, biomedicine, environmental remediation, and beyond.

In this manuscript, we report the facile fabrication of large-area model membranes with highly uniform and high aspect ratio pores with diameters <20 nm. These membranes are useful for fundamental investigations of separation by size exclusion in the ultrafiltration regime, where species to be separated from solution have dimensions of 1-100 nm. Such investigations require membranes with narrow pores and high aspect ratios such that the Hagen-Poiseuille equation is followed, enabling well-known models such as the hindered transport model to be evaluated and other affecting factors to be ignored. We demonstrate that the sub-20 nm pores in the membrane are of sufficiently high aspect ratio such that water flux through the membrane is consistent with the Hagen-Poiseuille equation. The fabrication relies on self-assembling block copolymers to form uniform, densely packed patterns with sub-20 nm resolution, sequential infiltration synthesis to convert the block copolymer in situ into a mask with adequate contrast to etch pores with an aspect ratio >5, and low-resolution photolithography to transfer the pattern over a large area into a silicon nitride membrane. Model membranes with narrow pore-size distribution fabricated in this way provide the means to investigate parameters that impact size-selective ultrafiltration separations such as the relationships between solute or particle size and pore size, their distributions, and rejection profiles, and, therefore, test the validity or limits of separation models.