Characterization Of Membranes Research Articles

Study of the influence of the basic-acidic nature of the non-solvent on the characteristics of membranes obtained by phase inversion

Study of the influence of the basic-acidic nature of the non-solvent on the characteristics of membranes obtained by phase inversion

The Janus-faced nature of complement in hemodialysis: interplay between complement, inflammation, and bioincompatibility unveiling a self-amplifying loop contributing to organ damage.

In hemodialysis (HD), complement activation, bioincompatibility, and inflammation are intricately intertwined. In the 1970s, as HD became a routine therapy, the observation of complement pathway activation and transient leukopenia by cellulosic dialysis membranes triggered the bioincompatibility debate and its clinical relevance. Extensive deliberations have covered definitions, assessment markers, scope, and long-term clinical consequences of membrane-dependent bioincompatibility reactions. While complement pathways' interplay with coagulation and inflammation has been delineated, HD's focus has primarily been on developing more biocompatible membranes using advanced technologies. Recent advances and understanding of the current HD delivery mode (4-hour sessions, thrice weekly) suggest that factors beyond membrane characteristics play a significant role, and a more complex, multifactorial picture of bioincompatibility is emerging. Chronic activation of the complement system and persistent low-grade "uremic inflammation" in chronic kidney disease (CKD) and HD lead to premature inflammaging of the kidney, resembling aging in the general population. Cellular senescence, modulated by complement activation and the uremic milieu, contributes to chronic inflammaging. Additionally, the formation of neutrophil extracellular traps (NETs, process of NETosis) during HD and their biological activity in the interdialytic period can lead to dialysis-induced systemic stress. Thus, complement-inflammation manifestations in HD therapies extend beyond traditional membrane-related bioincompatibility consequences. Recent scientific knowledge is reshaping strategies to mitigate detrimental consequences of bioincompatibility, both technologically and in HD therapy delivery modes, to improve dialysis patient outcomes.

Charge characteristics of co-electrospun nanofiber membranes and their application in high-humidity environment

Enhancing the charge density and charge stability is an important approach to improve the filtration performance of electrospun nanofiber air filters. In the present study, the polymers with different electron transport capabilities were co-electrospun in pairs to prepare charge-enhanced nanofiber membranes. The results showed that the average surface potential of the interfacial regions of polyamide 6 (PA6) and polyvinyl chloride (PVC) nanofibers was 165 mV, which was substantially higher than the non-intersection area of nanofibers. The charges induced by the contact-induced electrification between nanofibers accumulated in the intersection area of the hybrid nanofibers, which contributed to the high surface potential of the nanofiber membranes. Moreover, the co-electrospinning of polymers allowed the positively charged PA 6 nanofibers and negatively charged PVC nanofibers to coexist in the nanofiber membranes. Benefiting from these charge characteristics, the co-electrospun PA 6/PVC nanofiber membranes exhibited an average filtration efficiency of 99.73 % for 50–500 nm particles at the face velocity of 5.3 cm/s, and the pressure drop was 130 Pa. A hydrophilic fiber layer was employed to mitigate the influence of humidity on the charge decay and pressure drop growth of thenanofiber membrane. The growth rate of pressure drop of the protected nanofiber membrane was as low as 0.95 Pa/min under the challenge of water droplets. In contrast, the growth rate of pressure drop for common membrane based filters was in the range of 5–120 Pa/min. Additionally, the color of the hydrophilic layer changed corresponding to the water content in the air filters, which could serve as an indicator for the filter service life visible to naked eyes. This study provides a new approach for charging nanofiber membranes and improving their filtration performance stability in practical applications.

Application of machine learning tools to study the synergistic impact of physicochemical properties of peptides and filtration membranes on peptide migration during electrodialysis with filtration membranes

The present study aimed to explore the application of machine learning-based tools to study the impact of physicochemical properties of peptides and filtration membranes (FM) on peptide migration during electrodialysis with filtration membranes (EDFM). A total of 14 membranes characterized in terms of 10 physicochemical properties were employed to evaluate the selective migration of cationic and anionic peptides from a tryptic hydrolysate of whey protein isolate well characterized by chemometric and bioinformatic methods. Two machine learning approaches were compared: Decision Tree (DT) and Binary Greedy Network (BGN). Based on the feature selection and model performance results, DT appeared to be the most appropriate approach to generate explanatory models of peptide migration. From the selected DT models, selective migration patterns associated with specific physicochemical properties of peptides and FMs were established for the first time. The migration of anionic peptides was positively affected by higher average peak-to-valley roughness (Rz) values and macropores distribution in the filtrating layer (Mp-FL), where S11N+ and PES300 were the FMs providing the highest recovery of this type of peptides, particularly for those with isoelectric point (pI) values lower than 4.407 (IDALNENK, KYLLFCMENSAEPEQSLACQCLVRTPEVD, SLAMAASDISLLDAQSAPL, SLAMAASDISLLDAQSAPLR, TDYKKYLLFCMENSAEPEQ, TPEVDDEALEK, TPEVDDEALEKFDK, VLVLDTDYK, and VYVEELKPTPEGDLEILLQK) which reached average recovery rates of 16.617 and 4.556%, respectively. Regarding the migration of cationic peptides, this was mainly affected by other membrane characteristics such as volumetric porosity (Vp) and zeta potential (ZP), as well as peptide parameters such as polar residue content, pI, and leucine content. S11, S11SO3-, PES100, and PES300 were the FMs with the highest selective recovery rate for 7 out of 11 cationic peptides (ALPHMIR, IPAVFK, PMHI, PMHIR, TKIPAVF, TKIPAVFK, and VGINYWLAHK) with average values between 2.149 to 4.328%. This novel DT-based approach represents a suitable tool for studying peptide migration, choosing the most appropriate FMs for selective bioactive peptide migration during EDFM, and understanding the phenomena involved in their migration process.

Ultrafiltration membrane fouling control caused by extracellular organic matter extracted from Microcystis aeruginosa: role of visible light pre-photocatalysis and membrane characteristics

Ultrafiltration membrane fouling control caused by extracellular organic matter extracted from Microcystis aeruginosa: role of visible light pre-photocatalysis and membrane characteristics

The Chorioallantoic Membrane (CAM) Model: From Its Origins in Developmental Biology to Its Role in Cancer Research.

Over the past century, the chick embryo model, historically employed for research in developmental biology, has become a valuable tool for cancer research. The characteristics of the chick chorioallantoic membrane (CAM) make it a convenient model for the study of cancer, leading to the establishment of the CAM assay as an alternative to traditional in vivo cancer models. In this review we will explore the characteristics of the CAM that make it suitable for cancer research, as well as its consolidation as a versatile platform in this field. We will put particular emphasis on describing the key features that make this model an important asset for studying the hallmarks of cancer and for testing a wide variety of therapeutic strategies for its treatment, and which make it a suitable host for patient-derived xenografts (PDX). Additionally, we will examine the wide spectrum of methodological approaches available to study these subjects, highlighting some innovative cases. Finally, we will discuss the advantages and disadvantages of the chick CAM as a model for cancer research and how we can improve this model to its full potential.

Fabrication and characterization of carvacrol encapsulated gelatin/chitosan composite nanofiber membrane as active packaging material

In this study, carvacrol was effectively encapsulated in gelatin/chitosan composite nanofiber membrane using the electrospinning method with the help of the cationic surfactant cetyltrimethylammonium bromide (CTAB). The effects of CTAB (0.0 %, 1 %, w/w) and bioactive carvacrol (0.0 %, 1.0 %, 3.0 %, 5.0 %, 7.0 %, 10 %, w/w) on the structural, physicomechanical, antibacterial, and antioxidant characteristics of the nanofiber membranes were investigated. The results demonstrated that the antibacterial and antioxidant characteristics of the gelatin/chitosan composite nanofiber membrane (GC) and GC-CAR membrane (with the addition of 1.0 % carvacrol) were unsatisfactory. As carvacrol and CTAB were both added, the elongation at break, antibacterial, and antioxidant properties of the nanofiber membranes significantly improved (p < 0.05), while the water vapor permeability (WVP) significantly decreased (p < 0.05). When the added amount of carvacrol was 5 % (w/w), the nanofiber membrane (GC-CAR5-CTAB) exhibited the best antioxidant and antibacterial performance. Finally, the GC-CAR5-CTAB membrane was applied to the preservation of strawberries and Erjingtiao chilies, and their shelf life was effectively extended. The above results indicate that the nanofiber membrane prepared in this study has great potential for application in food-active packaging.

Unique dual superlyophobic covalent organic frameworks (COF-TpBD) intercalated MXene composite membrane for efficient oil-water separation

The development of composite membranes utilizing transition metal carbides and nitrides, exemplified by Ti3C2Tx (MXene), has proven efficacious in the treatment of oily wastewater. However, challenges arise from the prolonged and convoluted transport paths within MXene interlayer nanochannels, significantly impeding mass transfer and diminishing membrane permeability. This investigation incorporated porous covalent organic frameworks (COFs) as intercalating agents into two-dimensional (2D) MXene-based membranes to expand the interlayer nanochannels. The resulting MXene@COF-TpBD functional layer polyethersulfone (PES) composite membrane exhibited a distinctive dual superoleophobic surface, concurrently manifesting underwater superoleophobicity and underoil superhydrophobicity (underwater oil contact angle > 150°, underoil water contact angle > 150°). The membranes exhibited excellent water flux (up to 4092.7 L·m-2·h-1·bar-1), efficient oil-water emulsion separation (up to 1908.4 L·m-2·h-1·bar-1, rejection rates >99.78%), noteworthy fouling resistance and structural stability, outperforming most of existing similar membranes. Furthermore, supported by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the incorporation of COF-TpBD improved the antifouling characteristics of the composite membrane. This work presents innovative insights into the improvement of 2D MXene membranes and the use of COF-TpBD for the specific remediation of oily wastewater.

Experimental determination of the mechanical and hydrolytic properties of chitosan/rice husk ash composite membranes

Chitosan-based membranes are promising alternatives to synthetic membranes in a number of specialized use cases, including water purification and electrochemical devices. In application, excessive swelling when hydrated can lead to poor mechanical integrity, necessitating modifications to the polymer to counter this effect. Embedding inorganic fillers within an organic polymer matrix is one method of combining excellent mechanical stability with good performance. This study investigated the effect of rice husk ash (RHA) on the mechanical and hydrolytic properties of chitosan-based composite membranes. We incorporated varying amounts of RHA into a chitosan solution and prepared thin film membranes via solution casting. We performed structural, chemical, and mechanical characterizations on the ash and membranes, observing 82.84 % water uptake in the 1.5 wt% (wt%) RHA-doped membrane and 13.93 MPa tensile strength in the 2.0 wt% loaded composite. As the RHA content increased, the swelling ratio of the composites with RHA loadings greater than 1.0 wt% decreased, indicating an enhancement in mechanical strength. The observed results demonstrate that combining improved mechanical strength with increased water absorption and reduced swelling can lead to optimal membrane characteristics.

Intestinal Cells-on-Chip for Permeability Studies

Background: To accurately measure permeability of compounds in the intestine, there is a need for preclinical in vitro models that accurately represent the specificity, integrity and complexity of the human small intestinal barrier. Intestine-on-chip systems hold considerable promise as testing platforms, but several characteristics still require optimization and further development. Methods: An established intestine-on-chip model for tissue explants was adopted for intestinal cell monolayer culture. A 3D-printed culture disc was designed to allow cell culture in static conditions and subsequent permeability studies in a dynamic environment. Membrane characteristics and standardized read-outs were investigated and compared to traditional permeability studies under static conditions. Results: By starting cultures outside the chip in conventional wells plates, the new cell disc design could support accurate cell monolayer formation for both Caco-2 and human enteroids. When transferred to the chip with laminar flow, there was accurate detection of barrier integrity (FD4 and Cascade Blue) and permeability (atenolol/antipyrine). Both flow and membrane characteristics had a significant impact on permeability outcomes. Conclusions: This novel intestinal cell-on-chip system offers large flexibility for intestinal permeability studies, although it still requires validation with more compounds to reveal its full potential.

Preparation and Characterization of Nanocellulose/Sulfonated Poly(Ether Imide) Composite Membrane and Its Application as Proton Exchange Membrane

ABSTRACTThe TEMPO‐oxidized cellulose nanofibril (CNF) membrane is combined with sulfonated poly(ether imide) (SPEI) using the solution impregnation method to enhance its proton exchange membrane properties. SPEI solutions with different sulfonation levels, SPEI1, SPEI2, SPEI4, and SPEI5, are prepared by adjusting the acetyl sulfate to PEI mole ratios from 1:1 to 2:1, 3:1, 4:1, and 5:1, respectively. The CNF membranes are immersed in each SPEI solution for 24 h and hot‐pressed at 100°C for 1 h to form composite membranes. The chemical structure, morphology, wettability, and membrane characteristics are analyzed. The wettability of SPEI on the CNF surface varies with sulfonation degree, and it affects the morphology of each CNF‐SPEI membrane. Consequently, proton conductivity and ion exchange capacity (IEC) increase, while methanol permeability decreases with increasing sulfonation levels. The CNF‐SPEI5 membrane exhibits the highest proton conductivity of 4.23 mS.cm−1 and the lowest methanol permeability at 6.67 × 10−7 cm2.s−1. Additionally, the CNF‐SPEI4 membrane achieves maximum tensile strength and flexibility at 4.91 ± 0.09 MPa and 15.05% ± 0.24%, respectively. While its proton conductivity still faces challenges, the CNF/SPEI membrane demonstrates better methanol permeability suppression than Nafion 117 (1.31 × 10−6 cm2.s−1) and superior dimensional stability compared with the pristine CNF membrane.

Characteristics of Aliphitic and Aromatic Ion-Exchange Membranes after Electrodialysis Tartrate Stabilization of Wine Materials

Color indication of anthocyanins, FTIR spectroscopy, measurement of surface contact angle values, determination of specific electrical conductivity, as well as voltammetry and parallel measurement of pH of desalted solutions were used to analyze the fouling characteristics of aliphatic (CJMA-3, CJMC-3) and aromatic (AMX-Sb, CMX-Sb) ion-exchange membranes used in electrodialysis tartrate stabilization of wine material. It has been shown that polyphenols form complexes with metal ions on the surface and in the subsurface layers of cation-exchange membranes, which do not interfere with the transfer of cations. Foulants affect the magnitude of limiting currents and enhance water splitting at the surface of all studied membranes, and also reduce the electrical conductivity of anion-exchange membranes. The use of a pulsed electric field instead of a continuous direct electric current, traditional for electrodialysis, weakens the negative impact of foulants on membranes’ electrical conductivity. These data can be useful for selecting membranes and current modes when carrying out electrodialysis tartrate stabilization of wine materials.

Rethinking nanofiltration membrane design for breaking the trade-off in Li/Mg separation: A comprehensive analysis based on the separation factor-lithium flux (S-JLi) framework

Nanofiltration (NF) membranes are crucial for lithium (Li) recovery from salt-lake brine, but efficient Li/magnesium (Mg) separation remains challenging. This study employs the recently proposed S-JLi (separation factor vs Li flux) framework to evaluate NF membrane performance for Li/Mg separation, addressing limitations in traditional S-A (separation factor vs water permeance) frameworks. Using the Donnan Steric Pore Model with Dielectric Exclusion (DSPM-DE), we systematically investigate how operating conditions, feedwater properties, and membrane characteristics affect Li/Mg separation. Our results reveal that positively charged membranes outperform negatively charged ones, despite experiencing performance drops in high-salinity environments. We identify a trade-off between Li/Mg selectivity and Li flux that cannot be overcome by adjusting single membrane parameters. Multi-parameter synergistic regulation, particularly minimizing effective membrane thickness while optimizing charge density and pore size, emerges as a promising strategy to enhance separation performance. Our numerical simulations align well with experimental data, providing theoretical insights for designing high-performance Li/Mg separation membranes and emphasizing the importance of considering both selectivity and Li recovery in membrane development and evaluation.

Interpretation of antimicrobial function of biosurfactant rhamnolipids using Trisodium 8‐hydroxypyrene‐1,3,6‐trisulfonate‐based fluorescent surfactants

AbstractThe wide use of antibiotics can lead to antimicrobial resistance. Biosurfactant rhamnolipids are not prone to induce antimicrobial resistance due to their potential to target microbial membranes in both bacteria and fungi. However, the membrane interaction of anionic rhamnolipids with microbials has never been visually observed. This study applied previously synthesized anionic fluorescent Trisodium 8‐hydroxypyrene‐1,3,6‐trisulfonate (HPTS)‐based surfactants, with hydrophobic tails from C8 to C18, to examine their interaction with the plant pathogen Alternaria alternata. The antifungal potency of the surfactants exhibited a positive correlation with the increase in hydrophobic chain length, culminating in C16, which demonstrated the highest activity. Subsequently, a modest reduction in potency was noted for the C18. Fluorescence microscopy confirmed the membrane targeting of HPTS‐C16, and molecular dynamics simulations supported its specific membrane interaction. HPTS‐C16 was notably more effective against spores than mycelium, consistent with its binding affinity. This research provides a fluorescent method to dissect the relationship between surfactant properties and microbial membrane characteristics, guiding the development of antimicrobials to combat resistance.

Investigating Characteristics of Anion Exchange Membranes Utilizing Various Anion-Conducting Monomers for Water Electrolysis

Water electrolysis, a sustainable technology, converts electrical energy into chemical energy, producing hydrogen as a clean energy source and fuel. While both proton exchange membrane and anion exchange membrane water electrolysis (AEMWE) exist, the widespread adoption of AEMWE faces challenges due to the low ionic conductivity and chemical/mechanical instability of anion exchange membranes (AEMs). To overcome these hurdles and increase market penetration, there's a need to develop AEMs with low resistance and high durability, necessitating comprehensive research on the entire polymer structure. In this study, we focused on preparing various AEMs and analyzing their properties. We employed different anion-conducting monomers to create highly conductive and chemically/mechanically stable pore-filling AEMs for AEMWE. These pore-filling AEMs were fabricated by infusing and crosslinking anion-conducting monomers within a porous polyethylene substrate. We characterized these membranes in terms of areal resistance, ionic conductivity, ion exchange capacity, contact angle, water uptake, swelling ratio, mechanical strength, and hydrogen crossover. Additionally, we conducted performance and durability tests for AEMWE and discussed the findings. Acknowledgments This research was supported in part by Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ016253), Rural Development Administration, Republic of Korea and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.

Engineered surface design of recognition site-ordered biomimetic sensor for efficient detection of circulating tumor cells

The oriented assembly of cell membrane coating plays an important role in advancing the application of this strategy in biomedical fields, particularly in detecting circulating tumor cells (CTCs). Unfortunately, there is a formidable challenge in achieving effective membrane orientation during the coating process owing to the asymmetric properties of cell membranes. Herein, magnetic vesicles released by tumor cells were designed to break down these barriers in the same way that microvesicles are actively secreted from cells, which completely inherited the orientation and characteristics of the parent cell membranes, exhibiting a satisfactory self-targeting ability for homologous cells. To cope with the complex application environment, spatially ordered aptamers were integrated into magnetic vesicles and combined with catalytic hairpin assembly (CHA) technology to construct a recognition site-ordered biomimetic sensor for high-performance detection of CTCs. In this strategy, the ordered arrangement of membrane proteins and aptamers markedly improved capture efficiency of traditional biomimetic strategy for CTCs. Additionally, CHA-induced fluorescence and colorimetric analysis ensured the detection accuracy and sensitivity, with a linear range of 0 to 104 cells mL−1 and a low detection limit of 3 cells mL−1 for fluorometry and 6 cells mL−1 for colorimetry. Overall, the biomimetic sensor offered broader possibilities for detecting rare CTCs and provided new insight to expand the application of cell membrane biomimetic strategies in biomedicine.

On the directionality of membrane coupled Helmholtz resonators under open air conditions

Controlling the absorption and diffusion of sound in the audible range constitutes an exciting field of research. Acoustic absorbers and diffusers perform extraordinarily well at high frequencies with sizes comparable to the wavelength of the working frequency. Conversely, efficient low-frequency attenuators demand large volumes leading to unpractical sizes, and there is now interest in determining whether the size of the resonator can be reduced while not compromising – or perhaps even decreasing – the working frequency. One viable approach is through the use of metamaterials to enable the control of device dynamics such that heavy sub-wavelength attenuation can be efficiently realised. To achieve this goal, the theoretical (including a mathematical model and the use of finite element analysis) and experimental characterisation of 3D-printed membrane-coupled Helmholtz resonator (HR) acoustic metamaterials (AMMs) is explored. The results reveal good agreement between theory and experiments, and show that membrane-coupled HR AMMs feature heavy sub-wavelength acoustic attenuation (λ/55) while also showcasing directional responses under open air conditions. These features are explained by the interplay between resonator size, membrane characteristics, and the presence of two acoustic ports. It is anticipated that, together with recent advances on smart AMMs, these systems will foster new progress in the development of dynamic AMMs for wideband attenuation.

Recovery of low-concentration waste acid by electrodialysis: Modeling and validation

In light of the operational principles of Electrodialysis (ED), it is anticipated that this technology would significantly contribute to the recovery of waste acids through selective separation and subsequent proton concentration. However, the imperfect proton leakage characteristics of anion exchange membranes (AEMs) not only detrimentally affect the efficacy of ED-based acid recovery systems but also present considerable challenges for modeling endeavors. This study introduces a model based on the Nernst-Plank Equation at the cell pair scale, aimed at predicting ED performance. The model incorporates an empirical expression that links operational parameters, such as acid concentration and the concentration ratio between the concentrate and dilute compartments, to the permselectivities of AEMs in terms of anion transport numbers. Furthermore, both numerical and experimental analyses are performed to evaluate energy consumption across various operating conditions. The simulation outcomes derived from the proposed model exhibit a strong correlation with experimental data concerning acid transport (where the acid concentration increases from 0.25 M to 1.1 M through a two-stage concentration process), water migration (which demonstrates a nearly linear increase over time with applied currents, specifically a 15% increase under low-current conditions and a 100% increase under high-current conditions), and energy consumption. It is hoped that this model will aid in the design and optimization of ED-based acid reclamation processes, thereby enhancing their practical applications.

Biomimetic Dual‐Driven Heterojunction Nanomotors for Targeted Catalytic Immunotherapy of Glioblastoma

AbstractThe existence of the blood–brain barrier (BBB) and the characteristics of the immunosuppressive microenvironment in glioblastoma (GBM) present significant challenges for targeted GBM therapy. To address this, a biomimetic hybrid cell membrane‐modified dual‐driven heterojunction nanomotor (HM@MnO2‐AuNR‐SiO2) is proposed for targeted GBM treatment. These nanomotors are designed to bypass the BBB and target glioma regions by mimicking the surface characteristics of GBM and macrophage membranes. More importantly, the MnO2‐AuNR‐SiO2 heterojunction structure enables dual‐driven propulsion through near‐infrared‐II (NIR‐II) light and oxygen bubbles, allowing effective treatment at deep tumor sites. Meanwhile, the plasmonic AuNR‐MnO2 heterostructure facilitates the separation of electron–hole pairs and generates reactive oxygen species (ROS), inducing immunogenic tumor cell death under NIR‐II laser irradiation. Furthermore, MnO2 in the tumor microenvironment reacts to release Mn2+ ions, activating the cGAS‐STING pathway and enhancing antitumor immunity. In vitro and in vivo experiments demonstrate that these dual‐driven biomimetic nanomotors achieve active targeting and deep tumor infiltration, promoting M1 macrophage polarization, dendritic cell maturation, and effector T‐cell activation, thereby enhancing GBM catalysis and immunotherapy through ROS production and STING pathway activation.

Quantifying steric, non-steric, and adsorption contributions to solute rejection in covalent organic framework nanofiltration membranes

Solute transport in nanofiltration (NF) membrane systems is described with the Donnan Steric Pore Model with Dielectric Exclusion (DSPM-DE), which couples size- and charge-based solute partitioning mechanisms into and out of the membrane pores with flow through the pore, as described by the Extended Nernst-Planck equation. If membrane structural and chemical characteristics are well defined, the DSPM-DE can theoretically be used to identify solute rejection mechanisms, predict NF performance, and guide membrane design. However, the presence of additional separation mechanisms, like adsorption, and the heterogeneous, convoluted characteristics of traditional NF membranes challenge these goals. In this work, we apply covalent organic frameworks (COFs) as model NF materials to demonstrate control over the steric and non-steric partitioning and transport mechanisms in NF. We experimentally isolate and quantify the steric and non-steric contributions to solute partitioning and transport in NF via application of the DSPM-DE to COF membranes fabricated with tailored pore sizes, thicknesses, and charge properties. We also demonstrate enhanced non-steric solute rejection achieved through changes to COF membrane structure and chemistry, and we highlight the significant impact of adsorption on measured solute rejection by COF membranes.