Membrane Performance Research Articles

Enhanced water permeability and antifouling properties of cross-linked graphene oxide composite membranes with tunable d-spacings

Low flux and membrane fouling are major challenges in membrane distillation (MD) for treating concentrated wastewater. This study compared the performance of GO composite membranes with different interlayer distances, by covalently bonding the terminal amine groups of ethylenediamine (EDA) and 1,12-diaminododecane (DADD) with the carboxyl groups present on the GO sheets. The results indicated that the GO-DADD/PTFE membrane, with longer carbon chain cross-linking, achieved the highest flux and antifouling properties. At 70 °C, the pure water flux reached 68.5 kg/m2·h, and the fluxes for treating NaCl, HA containing NaCl, and BSA containing NaCl were 29.8 %, 37.1 %, and 38.5 % higher than the uncrosslinked GO/PTFE, and 95.7 %, 121.2 %, and 146.9 % higher than the PTFE membrane, respectively. Through mathematical models for mass and heat transfer, the study identified the key to this enhancement as the increased d-spacing within the GO layer due to cross-linking, which weakened the Kelvin effect and enhanced the vapor partial pressure on the hot side. The unique surface structure and electrostatic interactions induced by long-chain cross-linking further boosted the antifouling effect. These modifications not only overcome the typical trade-off between retention rates and flux but also offer a scalable and efficient solution for advanced membrane distillation applications.

Chitin-augmented wetting resistance and water-in-oil emulsion separation performance of silane-modified polyketone membrane

The utilization of membrane technology for separating water-in-oil (W/O) emulsions necessitates a membrane possessing high hydrophobic properties. However, the use of naturally hydrophobic membrane materials, such as polyvinylidene fluoride, is undesirable due to the persistence of fluorine-containing compounds in the environment. Polyketone (PK) membranes present a potential alternative, but their inherent hydrophilic properties can hinder the W/O emulsion separation process. To address this issue, hydrophobic modification of PK membranes can improve their performance in separating W/O emulsion. Natural hydrophobic materials like chitin offer a more sustainable alternative compared to synthetic materials. Chitin was introduced onto the membrane surface along with hexadecyltrimethoxysilane (HDTMS) subsequent to the initial reaction of the PK membrane with tetraethyl orthosilicate (TEOS). Comparative analysis revealed that the mixed chitin and HDTMS modification resulted in the lowest surface wettability compared to membrane modification using only TEOS, HDTMS, and chitin. Examination of membrane performance through toluene emulsion separation demonstrated increased permeability after modification, with permeate toluene purity over 99.8 %. Additionally, the chitin and silane-modified PK membrane exhibited a two-fold increase in filtration process permeability, indicating outstanding fouling resistance. These findings underscore the potential of natural compounds in imparting desired hydrophobic properties to membranes while minimizing reliance on synthetic materials.

Cyclodextrin-modified PVDF membranes with improved anti-fouling performance

The design of hydrophilic polyvinylidene fluoride (PVDF) membranes with anti-fouling properties has been explored for decades. Surface modification and blending are typical strategies to tailor the hydrophilicity of PVDF membranes. Herein, cyclodextrin was used to improve the antifouling performance of PVDF membranes. Cyclodextrin-modified PVDF membranes were prepared by coupling PVDF amination (blending with branched polyethyleneimine) and activated cyclodextrin grafting. The blending of PEI in the PVDF casting solution preliminarily aminated the PVDF, resulting in PEI-crosslinked/grafted PVDF membranes after phase inversion. Aldehydes groups on cyclodextrin, introduced by oxidation, endow cyclodextrin to be grafted on the aminated PVDF membrane by the formation of imines. Borch reduction performed on the activated cyclodextrin-grafted PVDF membrane converted the imine bonds to secondary amines, ensuring the membrane stability. The resulting membranes possess excellent antifouling performance, with a lower protein adsorption capacity (5.7 μg/cm2, indicated by Bovine Serum Albumin (BSA)), and a higher water flux recovery rate (FRR = 96%). The proposed method provides a facial strategy to prepare anti-fouling PVDF membranes.

On the role of the porous support membrane in seawater reverse osmosis membrane synthesis, properties and performance

In this study, we explore the role of the polysulfone (PSU) support membrane skin-layer and whole-body pore morphology on the physical-chemical properties and separation performance of hand-cast polyamide-PSU (PA-PSU) composite seawater reverse osmosis (SWRO) membranes. We tailor the support membrane pore morphology by varying the PSU concentration and the coagulation bath temperature. In order to isolate the impacts of the PSU support, all of the porous supports are coated using identical m-phenylene diamine (MPD) and trimesoyl chloride (TMC) solution compositions, reaction conditions, and post-treatments. As PSU concentration increases, PSU support membrane pore size, surface and body porosity, water permeability, MPD mass uptake (by the PSU support), and PA-PSU composite membrane water permeability decrease, while MPD and TMC conversion, PA film mass and thickness, crosslinking degree (XD), and PA-PSU composite membrane NaCl rejection increase. As PSU support membrane coagulation bath temperature increases, support membrane pore size, surface and body porosity, MPD uptake, PA film mass, thickness and XD, MPD and TMC conversion, and NaCl rejection increase, while composite PA-PSU membrane water and NaCl permeability decrease. Composite membrane permeabilities were 70–90 percent of the (theoretical) unsupported PA film permeabilities due to the high XD and low PA coating film thickness. Composite PA-PSU membrane water/salt permeabilities both correlate most strongly with PA coating film mass/thickness and XD, which in turn correlate most strongly with TMC conversion. The key to increasing water permeability is lower PA film mass/thickness and XD with higher support membrane surface pore size and porosity. In contrast, the key to increasing NaCl rejection is higher PA film mass/thickness and XD with lower support membrane surface pore size and porosity.

The impact of PAC-loaded polymer membrane thickness on chloroform removal and comparison of solvent and thermal membrane regeneration methods.

Powdered activated carbon (PAC) has better adsorption performance than granular activated carbon (GAC) and is widely used in water purification. In most cases, PAC is dosed into water directly, then precipitated as sludge, and landfilled. In this study, PAC was mixed with a polymer and dissolved in dimethylformamide (DMF) solvent to form a PAC-loaded membrane, which was then tested for chloroform removal. The chloroform adsorption capacity of the PAC membrane increased with increasing membrane thickness because of higher carbon loading. However, regardless of membrane thickness, the flux of the PAC membranes was similar since flux resistance predominantly occurred at the top dense polymer surface. This dense surface can be removed by sandpaper polishing, where the adsorption capacity of the polished PAC membranes was 20% higher than the unpolished membranes because of more even distribution of feed water on the polished surface. Removal of the dense surface via polishing increased the flux by 97% to 130%, exceeding the flux of typical household carbon block filters. Using DMF to regenerate the membrane recovered 48% to 66% of the initial adsorption capacity. Thermal regeneration of the exhausted PAC membrane at 250°C was more effective than DMF regeneration (both in terms of cost and performance), with 83% to 94% PAC membrane regeneration efficiency over four regeneration recycles. After four thermal regeneration cycles, flux increased by 300% and the membrane became brittle because of thermal aging of the polymer, indicating that a total of 6h of regeneration time (equivalent to three cycles in this study) was the limit for effective PAC membrane performance. PRACTITIONER POINTS: Powdered activated carbon was immobilized on a membrane to remove chloroform from water. Thicker membranes increased adsorption capacity but did not impact flux. Flux and capacity increased using polishing to remove the dense polymer surface and more evenly distribute flow across the membrane. Thermal regeneration of the membrane at 250°C was effective for up to three cycles and outperformed solvent-based regeneration. PAC-loaded filters are relevant for applications such as household carbon block filtration.

Investigating dialysis membrane surface charge and hydrophobicity effects on fibrinogen adsorption using synchrotron radiation micro-computed tomography (SR-CT)

Hemodialysis, a critical treatment for end-stage kidney disease (ESKD), efficiently eliminates toxic metabolic waste from the bloodstream. This study probes the complex interactions among surface charge, wettability, and roughness of Polyethersulfone (PES) membranes and their influence on fibrinogen (FB) adsorption, a key culprit in membrane fouling that compromises the dialysis efficacy. Utilizing non-invasive X-ray synchrotron-based micro-tomography (SR-CT), we analyzed an array of PES membranes—ranging from unmodified to superhydrophobic surfaces achieved via surface hydrophobization or hydrophobic mixed matrix methods, heparin-immobilized versions, zwitterionically coated with sulfobetaine and carboxibetaine, and uremic metabolite-modified membranes, each with intensified coatings. Our findings highlight that superhydrophobic membranes, particularly hydrophobic mixed matrix membrane, significantly repel FB, reducing fouling due to their high contact angle. Additionally, membranes with lower surface charges corresponded with lower protein adsorption, emphasizing the pivotal role of electrostatic interactions. Intriguingly, hydrophobic membranes outperformed their hydrophilic counterparts despite having higher surface roughness, suggesting that peak hemodialysis membrane performance is achieved through a synergistic balance of reduced surface charge and enhanced hydrophobicity. These insights drive home the importance of integrating charge, wettability, and texture considerations in membrane design to foster the next generation of low-fouling, high-performance hemodialysis membranes.

Atomistic understanding of Ti3C2 MXene membrane performance for separation of nitrate ions from aqueous solutions

Water desalination, which is a reliable method for providing drinking water and a suitable solution, as well as the membrane filtration method in wastewater treatment, has increased significantly in recent years. In this research, the separation of nitrite and nitrate ions from aqueous solutions was done using the MXene membrane of the Ti3C2 type using molecular dynamics simulation. In this study, various parameters, such as pore size MXene structure, characteristics of cavities, applied pressure, and flux were investigated. To investigate the removal of toxic pollutants from water, water flux, potential mean force, distribution of water molecules, and density were investigated. The results showed that the amount of penetration through the membrane increased with the increase in pressure. It was observed that by applying pressure to the system, the number of water molecules accumulated in front of the membrane decreases because they quickly pass through the membrane, which indicates the positive effect of increasing pressure on the separation rate of molecules. The permeability of this membrane was several times higher than the existing membranes in the industry. So that Mexene membranes, which consist of at least two layers, can repel ions with 100% success.

The Effect of GO on TiO2-doped PVDF Nanofiltration Membrane Performance: Synergistic Filtration of Large and Small Molecules Facilitated the Removal of Small Molecule Contaminants

The Effect of GO on TiO2-doped PVDF Nanofiltration Membrane Performance: Synergistic Filtration of Large and Small Molecules Facilitated the Removal of Small Molecule Contaminants

Introduction of polymeric ionic liquids containing quaternary ammonium groups to construct high-temperature proton exchange membranes with high proton conductivity and stability

A series of membrane materials suitable for high-temperature proton exchange membranes (HT-PEM) were successfully prepared by introducing polymeric ionic liquids (PILs) containing quaternary ammonium groups into ether-bonded polybenzimidazole (OPBI). The structure of the cross-linked membrane has a strong interaction with phosphoric acid (PA), which enhances proton transport and PA retention. To ensure better overall performance of the cross-linked membrane, the optimal PIL content is 30 wt% (OPBI-PIL-30 %). The PA uptake of OPBI-PIL-30 % membrane was 323.24 %, and the proton conductivity at 180 ℃ was 113.94 mS cm−1, which was much higher than that of OPBI membrane. It is noteworthy that the PA retention of OPBI-PIL-30 % membrane could reach 71.38 % after 240 h of testing under the harsh environment of 80 ℃/40 % RH. The membrane showed better acid retention capacity of 86.89 % at 160 ℃ under anhydrous environment. The OPBI-PIL-20 % membrane achieved the maximum power density of 436.19 mW cm−2, attributed to its favorable mechanical characteristics and proton conductivity. By these excellent properties, it is shown that OPBI-PIL-X membranes containing quaternary ammonium groups have the potential to be applied in high temperature proton exchange membrane fuel cells (HT-PEMFCs).

Performance of Chitosan/Carbon Nanotube-Coated Ultrafiltration Membranes for Natural Organic Matter Removal from Drinking Water

The objective of this study is to improve the filtration efficiency of commercially available polyethersulfone (PES) ultrafiltration (UF) membranes, with a specific focus on removing natural organic matter (NOM) and preventing membrane fouling. The modification of UF membranes was accomplished by utilizing chitosan/multi-walled carbon nanotubes (CS/MWCNT-OH) and employing both dip and spin coating techniques. The membrane surface morphologies were evaluated using the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Energy-Dispersive X-ray Spectroscopy (EDX) techniques. Tests were carried out to assess the effectiveness of the membranes in a laboratory-scale system using two primary water sources from Istanbul, specifically the Melen River and Terkos Lake. Total organic carbon (TOC), UV254 absorbance, turbidity, and trihalomethane formation potential (THMFP) were all measured as part of a thorough analysis. The surface morphology investigations verified the effective deposition of MWCNT-OH nanoparticles onto the membrane surface. This was corroborated by the reduction in the water contact angle, showing an improvement in the hydrophilicity of the membrane. The modified membranes demonstrated much higher TOC removal rates compared to the original membranes. Specifically, the removal efficiencies for Melen River and Terkos Lake were 37.14% and 56.86%, respectively. Nevertheless, the alteration of the surface led to a decline in membrane flux as a result of the concurrent drop in pore size. To summarize, the results of this work highlights the considerable capability of surface modification using CS/MWCNT-OH to improve the performance and antifouling characteristics of commercial PES UF membranes.

Impacts of high salinity on antifouling performance of hydrophilic polymer-modified reverse osmosis (RO) membrane

Reverse osmosis (RO) is a crucial process for treating waters across various salinity levels, but membrane fouling persists as an inherent challenge. While surface modification with hydrophilic polymers such as polyethylene glycol (PEG) and its derivatives is a prevailing strategy to alleviate fouling, its effectiveness has primarily been explored in low-salinity conditions, leaving a critical knowledge gap regarding the performance of such membranes in high-salinity environments and their susceptibility to feed salinity variations. We here investigated the antifouling characteristics of PEG-modified RO membranes for high-salinity wastewater and seawater treatment. Remarkably, our findings indicated a substantial decrease in fouling resistance under high-salinity conditions compared to low-salinity wastewaters used as control. The reduction in Lewis acid-base interactions, induced by decreased water structuring, was found to be a critical factor for the diminished fouling resistance based on the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) analysis. Complementary experimental and theoretical studies unveiled the disruptive role of high-concentration NaCl on PEG-water hydrogen bonds, causing PEG dehydration and configurational compression, which thus compromised the enthalpic barrier and entropic repulsion against fouling. Our study emphasizes the pivotal role of feed salinity in determining the fouling resistance of membranes modified with hydrophilic polymers, a factor often neglected in prior research.

High-performance double-separation-layer pervaporation membranes for ethanol dehydration

Pervaporation membranes are used to dehydrate ethanol, but standalone sodium alginate (SA) and polyvinyl alcohol (PVA) membranes pose challenges owing to their inherent issues, such as low stability and limited separation performance. Despite employing various complex and costly membrane preparation methods to address these shortcomings, the improvement in separation performance, especially in permeate flux, remains limited. In addition, the complexity and costliness of these methods hinder their industrial applications. Herein, we developed a simple and cost-effective method to prepare high-performance pervaporation membranes. First, a SA solution was cast on the polyacrylonitrile (PAN) bottom membrane to form a SA separation layer, and subsequently a PVA separation layer was applied atop of the SA separation layer, yielding double-separation-layer PVA/SA/PAN membranes. The smooth, compact and hydrophilic SA intermediate layer apparently decreased the defects in the PVA separation layer and the presence of the PVA separation layer isolated the SA layer from the liquid feed on the outer side and inhibited the swelling of SA separation layer, leading to high selectivities and stabilities. Under operating conditions of 69°C and a feed ethanol concentration of 90 wt%, the permeate flux and separation factor of the PVA4/SA/PAN membrane are 1201 g m−2 h−1 and 5164, respectively. Notably, the pervaporation separation index (PSI) of this membrane is 79 times that of the PVA4/PAN membrane. Moreover, the membrane performance remained stable over a continuous 10-day operation at 69°C, affirming its reliability and durability. We successfully prepared a high-performance two-separation-layer pervaporation membrane for ethanol dehydration.

Low MWCO non-polyamide nanofiltration membranes synthesized in aqueous by coupling with catechol-amine chemistry and the oxidation-induced self-polymerization of m-phenylenediamine

Catechol-amine coatings offer versatile routes for surface modifications and nanofiltration (NF) membrane preparations. However, the formation of the selective layer is time-consuming and often deficient, rendering it unsuitable for large-scale applications. In this work, oxidation-induced self-polymerization and catechol-amine chemistry were combined to rapidly construct nanofiltration membranes in an aqueous medium. M-phenylenediamine (MPD) underwent oxidation and self-polymerized on a polysulfone (PSF) support. The addition of sodium periodate facilitated the subsequent tannic acid (TA) coating. The catechol-amine reaction between oxidized TA and poly-MPD forms crosslinked poly TA-MPD complexes, offering the resulting membrane a high selectivity. The role of NaIO4 in the selective layer formation and the influences of the synthesis parameters on the membrane performance were discussed. Utilizing the facile method enabled the achievement of a low molecular weight cut-off (MWCO) NF membrane (180 Da). The membrane exhibited a high water permeance (10.9 Lm−2h−1bar−1) and good salt rejections (93 % for Na2SO4). The filtration of the bovine serum acid (BSA) solution demonstrated the membrane has good antifouling performance with a flux recovery ratio (FRR) of 95.1 %. The proposed method offers a straightforward and rapid approach to fabricating low MWCO NF membranes in an aqueous medium, which has potential in large-scale applications.

Recycling and 3D-Printing Biodegradable Membranes for Gas Separation-toward a Membrane Circular Economy.

Polymer membranes employed in gas separation play a pivotal role in advancing environmental sustainability, energy production, and gas purification technologies. Despite their significance, the current design and manufacturing of these membranes lack cradle-to-cradle approaches, contributing to plastic waste pollution. This study explores emerging solutions, including the use of biodegradable biopolymers such as polyhydroxybutyrate (PHB) and membrane recycling, with a focus on the specific impact of mechanical recycling on the performance of biodegradable gas separation membranes. This research represents the first systematic exploration of recycling biodegradable membranes for gas separation. Demonstrating that PHB membranes can be recycled and remanufactured without solvents using hot-melt extrusion and 3D printing, the research highlights PHB's promising performance in developing more sustainable CO2 separations, despite an increase in gas permeability with successive recycling steps due to reduced polymer molecular weight. The study emphasizes the excellent thermal, chemical, and mechanical stability of PHB membranes, albeit with a marginal reduction in gas selectivity upon recycling. However, limitations in PHB's molecular weight affecting extrudability and processability restrict the recycling to three cycles. Anticipating that this study will serve as a foundational exploration, we foresee more sophisticated recycling studies for gas separation membranes, paving the way for a circular economy in future membrane technologies.

Enhancing anti-fouling performance of ceramic membranes through iron oxide modification for the separation of oil-containing fermentation broth

Ceramic membranes are increasingly recognized for their effectiveness in processing fermentation broths. However, developing ceramic membranes with superior anti-fouling properties remains a challenge for large-scale applications. Iron oxide nanomaterials have gained significant research interest as a cost-effective and readily available solution for mitigating membrane fouling, thanks to their excellent hydrophilicity. This study introduces ceramic membranes enhanced with iron oxide via a facile sol-gel technique. The membrane's resistance to fouling, hydrophilicity, adhesion force, and surface potential were assessed. Post-modification, a consistent distribution of iron elements on the membrane surface was achieved, with negligible alteration in pore size. Although the pure water permeance (450 ± 45 L m−2 h−1·bar−1) did not change significantly, the permeance of the modified membrane (225 L m−2 h−1·bar−1) was nearly 20 % higher than that of the original membrane when separating a 1000 ppm oil-in-water emulsion, with both membranes achieving 99 % oil droplet rejection. Moreover, the flux recovery rate of the modified membrane surpassed that of the original membrane by approximately 30 %, indicating a significant improvement in anti-fouling performance. Upscaling experiments further validated the modified membrane's anti-fouling performance and capability to rapidly process broths with high oil content. Overall, this study presents a novel anti-fouling ceramic membrane for the treatment of oil-containing fermentation systems.

Structure design and performance optimization of PVDF-CTFE nanofibrous composite nanofiltration membrane modified by C–Cl active site grafting

The substrate membrane plays a crucial role in determining the performance of composite nanofiltration membranes prepared by interfacial polymerization (IP). In this study, persistent hydrophilic modification of polyvinylidene fluoride-co-chlorotrifluoroethylene (PVDF-CTFE) was achieved by incorporating N-methylglucamine (N-MG) without altering the membrane's morphology or pore size. Moreover, thin-film nanofibrous composite (TFNC) nanofiltration membranes were prepared using the surfactant assembly regulated interfacial polymerization (SARIP) method with the modified PVDF-CTFE@N-MG nanofibrous membrane as the substrate. The effect of N-MG addition on the substrate membrane's hydrophilicity and the structure and performance of the polyamide (PA) separation layer was investigated. The results showed that the addition of N-MG significantly improved the hydrophilicity of the PVDF-CTFE nanofibrous membrane. The TFNC-5 membrane, prepared with the modified PVDF-CTFE@N-MG nanofibrous membrane as the substrate, exhibited permeability exceeding 13.5 L m−2 h−1·bar−1 for various dye solutions at 3 bar pressure, with rejection rates above 98 %. It also demonstrated excellent selective separation performance (separation factor for NaCl/Orange G reaching 97.38) and long-term operational stability. This work provides a method for the preparation of low-pressure, high-flux nanofiltration membranes, which is applicable to seawater desalination and dye wastewater treatment.

Quantitative analyzing the effect of pore distribution on formation of active layer for forward osmosis membrane

The morphology and performance of polyamide active layer can be controlled by the pore size and surface porosity of support layer. Nevertheless, further investigation is required to elucidate the impact of pore distribution and the specific role of each pore. Therefore, by introducing polyetherimide (PEI) as a sacrificial top layer, the support layer with a wide pore distribution was prepared by co-casting method. A mathematical model was developed to enable the estimation of the impact of each pore radius and pore distribution on the structure and performance of the active layer. During interfacial polymerization process, the surface pore size and distribution of the support layer influenced the incipient film which consists of the polyamide colloids and dominates the successive growth of polyamide layer. It was suggested that both average pore radius and pore distribution contributed to the composite of incipient film. The overall η of 1.77 for S75 corresponded to an incipient film composed of linear polyamide terminated with MPD and fully cross-linked polyamide, resulting in the best performing membrane (C75) with DC of 0.75 and structural parameter as low as 230 μm. A comparison of C75 with C0 revealed an increase in water flux of 138 % and a minor increase in salt flux of 6.37 %. This work presents a novel approach to enhancing the performance of FO membranes and offers a new perspective on the structure-effect relationship.

A polymeric structural approach to improving proton-blocking performance in anion exchange membranes for electrochemical systems

Anion exchange membranes are crucial in processes involving acids and bases, yet they often suffer from proton leakage, which diminishes system efficiency and membrane durability. To tackle this challenge, a novel polymeric structural approach was assessed to enhance proton-blocking performance. This approach scrutinized the interaction between protons and proton-attracting chemical species in the presence or absence of dimethyl (DM) groups within the poly(phenylene oxide) structure, and compared with the commercially available poly(aryl piperidinium) (PiperION) membrane containing strongly hydrophobic -CF3 groups. The findings revealed proton-blocking efficiencies of 60 % for PiperION, 62 % for PPO, and 72 % for DMPPO, with corresponding proton permeabilities of 36.71 × 10−6 cm2·s−1, 17.30 × 10−6 cm2·s−1, and 7.58 × 10−6 cm2·s−1, respectively. These results suggest enhanced proton-blocking performance with DM groups, while -CF3 groups do not provide a substantial improvement. Moreover, PPO-based membranes, when reinforced as composites, demonstrated superior proton-blocking capabilities compared to non-reinforced counterparts. These findings underscore the significance of designing anion exchange membranes with reduced proton interactions to achieve optimal proton-blocking performance in electrochemical systems.

Performance of proton exchange membrane fuel cell system by considering the effects of the gas diffusion layer thickness, catalyst layer thickness, and operating temperature of the cell

BackgroundIn this research, the effect of anode and cathode channel cross-sectional shape on the performance of PEM fuel cell was investigated and the appropriate length and dimensions of the channel were determined. Finally, for the determined geometric conditions, the cell performance at different voltages was investigated. MethodsThe purpose of this study was to investigate the structural characteristics of the fuel cell on its performance. The results show that the pressure and temperature in the catalyst layer (CL) of the cathode side are greater than the anode, and the temperature in the central regions of the catalyst layer is higher than the lateral regions. Also, the channel with a length of 100 mm is optimal in terms of producing the maximum current density and the amount of pressure drop is much lower than the channel with a length of 150 mm, which reduces the power consumption of the cell. Significant findingsIn general, a higher electric current is produced by increasing the thickness of the gas diffusion layer (GDL) and the catalyst layer. At a voltage of 0.8 V, with increasing thickness from 0.25 mm to 0.5 mm, the current density increases above 6 %. The percentage increase in current density at 60 °C–80 °C for 0.85 V and 0.75 V voltages is 42.1 % and 9.28 %, respectively.

Integrated-omics profiling unveils the disparities of host defense to ECM scaffolds during wound healing in aged individuals

Extracellular matrix (ECM) scaffold membranes have exhibited promising potential to better the outcomes of wound healing by creating a regenerative microenvironment around. However, when compared to the application in younger individuals, the performance of the same scaffold membrane in promoting re-epithelialization and collagen deposition was observed dissatisfying in aged mice. To comprehensively explore the mechanisms underlying this age-related disparity, we conducted the integrated analysis, combing single-cell RNA sequencing (scRNA-Seq) with spatial transcriptomics, and elucidated six functionally and spatially distinctive macrophage groups and lymphocytes surrounding the ECM scaffolds. Through intergroup comparative analysis and cell-cell communication, we characterized the dysfunction of Spp1+ macrophages in aged mice impeded the activation of the type Ⅱ immune response, thus inhibiting the repair ability of epidermal cells and fibroblasts around the ECM scaffolds. These findings contribute to a deeper understanding of biomaterial applications in varied physiological contexts, thereby paving the way for the development of precision-based biomaterials tailored specifically for aged individuals in future therapeutic strategies.