Search Results (313)

The increasing discharge of cobalt-containing effluents from metallurgical, electroplating, and battery-related industries necessitates the development of efficient and stable separation technologies. In this study, a sodium dodecyl sulfate (SDS)-assisted micellar-enhanced ultrafiltration (MEUF) process was systematically evaluated for the removal of Co²⁺ from aqueous solutions using a flat-sheet polyethersulfone (PES) membrane operated under crossflow conditions. The effects of surfactant concentration, initial solution pH, cobalt concentration, background electrolyte, and extended filtration time were examined to assess process performance and operational stability. Direct ultrafiltration of 50 mg L⁻¹ Co²⁺ without surfactant resulted in limited rejection (~18%). The introduction of SDS markedly improved removal efficiency, achieving >99% rejection at and above 1 critical micelle concentration (CMC). An SDS dosage of 1 CMC provided an optimal balance between permeate flux (~155 L m⁻² h⁻¹) and cobalt removal (>99%). The system maintained high rejection efficiency across a pH range of 3–9, demonstrating robust cobalt–micelle interactions. Increasing the initial cobalt concentration from 10 to 50 mg L⁻¹ caused a moderate decline in flux but did not significantly affect rejection efficiency. In contrast, elevated ionic strength due to NaNO₃ addition reduced both flux and cobalt removal, highlighting the influence of competing ions on micelle-mediated separation. Long-term continuous operation for 40 h showed stable permeate flux and sustained cobalt rejection above 99%, indicating minimal fouling. FTIR and SEM–EDS analyses confirmed membrane chemical stability and negligible cobalt deposition. These findings demonstrate that SDS-based MEUF is an effective and operationally stable approach for cobalt removal from contaminated water systems. Full article

Fouling limits the performance and lifetime of polyethersulfone (PES) ultrafiltration membranes. We investigated the effect of blending polyaniline (PAni·DBSA) into PES on membrane morphology, wettability, permeability and antifouling behavior, and we evaluated a simple electrochemical cleaning protocol for fouled membranes. A series of PES/PAni·DBSA membranes with different PAni loadings were characterized by SEM, BET, AFM, contact angle, TGA and porosity analysis. Initial water flux (J), bovine serum albumin (BSA) rejection (RR) and flux recovery ratio (FRR) were measured in a dead-end filtration cell. Electrochemical cleaning was applied to selected fouled membranes, and post-cleaning flux and rejection were measured. PAni·DBSA incorporation produced a hierarchical pore structure and altered near-surface texture. Contact angle decreased from 76° to 54°, and swelling increased for intermediate PAni loadings. Initial pure-water fluxes ranged from 5.9 to 39.3 L·m⁻²·h⁻¹. When expressed as absolute percentages, the best performing membrane in terms of reversible fouling recovered 8.12 times of its initial flux. Multivariate analysis indicates that surface hydration and height distribution explain more variance in FRR than Rq alone, consistent with a synergistic role of texture and wettability. Electrochemical treatment substantially increased both flux and rejection for tested membranes, indicating effective foulant mobilization. Full article

Forward osmosis (FO) membranes have garnered widespread research interest in water treatment, yet their permeability–selectivity trade-off, internal concentration polarization, and membrane fouling remain critical challenges. Herein, a chitooligosaccharide/polydopamine (COS/PDA) co-deposition strategy was proposed to modify polyethersulfone (PES) substrates for constructing high-performance thin-film composite (TFC) FO membranes. COS suppressed excessive PDA aggregation, reduced substrate roughness, and improved substrate hydrophilicity. This substrate modification regulated interfacial polymerization by increasing the adsorption capacity for m-phenylenediamine (MPD) while slowing its diffusion rate, thereby forming thinner, smoother, and more densely crosslinked polyamide (PA) layers. The optimized C₄P₁-TFC membrane delivered water fluxes of 42.2 and 23.5 L m⁻² h⁻¹ in pressure-retarded osmosis (PRO) and FO modes, respectively, representing 43.1% and 40.2% improvements over the pristine membrane. Its specific salt flux decreased to 0.07 and 0.15 g L⁻¹ in the two modes, respectively, suggesting enhanced selectivity. Meanwhile, the C₄P₁-TFC membrane showed antibacterial rates of 85.7% against Escherichia coli and 86.9% against Staphylococcus aureus, together with improved antifouling performance against bovine serum albumin and lysozyme. This work presents a simple and effective co-deposition approach for simultaneously improving the separation, antibacterial, and antifouling performance of TFC FO membranes, showing promising potential for practical applications. Full article

High-performance polyethersulfone (PES) ultrafiltration membranes integrating antibacterial activity and antifouling performance were fabricated via the in situ construction of bimetallic polyphenol networks (BMPNs) throughout the membrane architecture. Tannic acid (TA) functioned as a multifunctional molecular bridge, functionalizing silver metal–organic frameworks (Ag-MOFs) to yield hydrophilic T-Ag-MOFs and chelating Fe³⁺ ions from the coagulation bath to form a polyphenol network during phase inversion. T-Ag-MOF incorporation generated asymmetric morphologies featuring highly porous surfaces and sponge-like cross-sections, improving pure water permeability, mechanical integrity, and bovine serum albumin (BSA) rejection. TA-mediated functionalization increased hydrophilicity, imparted a negative surface charge, suppressed nonspecific protein adhesion, and enhanced flux recovery with low irreversible fouling. At an optimal loading of 0.4 wt%, the resultant T-Ag-MOF/Fe³⁺/PES composite membrane achieved a pure water permeability of 593.4 L m⁻² h⁻¹ bar⁻¹—1.77-fold higher than that of the pristine PES control—while sustaining a BSA rejection of 96.5%. Notably, interfacial compatibility between the T-Ag-MOFs and PES matrix was enhanced, facilitating strong, covalent-like filler–matrix adhesion. Moreover, the composite membrane delivered synergistic multifunctionality, including exceptional long-term aqueous stability, precisely tuned Ag⁺ release kinetics, and potent antibacterial activity, as evidenced by negligible uncontrolled ion leaching and a lack of structural degradation under prolonged hydration. Full article

Antimicrobial resistance genes threaten the effective treatment of infectious diseases, underscoring the importance of their control in line with the EU One Health policy. Wastewater treatment plants are recognized hotspots for antimicrobial resistance. We assessed whether multi-channel mixed-matrix membranes (MCMMMs)—polyethersulfone (PES)/polyvinylpyrrolidone (PVP) ultrafiltration membranes with embedded activated carbon—can concurrently reduce microorganisms and extracellular DNA in wastewater effluent, building on prior reports of micropollutant removal. We evaluated the performance of MCMMMs in removing Escherichia coli and Saccharomyces cerevisiae as model organisms, as well as colony-forming units (CFUs) from wastewater effluent at a transmembrane pressure of 1 bar with a filtration area of 66 cm² over 1 h. DNA was extracted from wastewater effluent following filtration and analyzed to assess changes in microbial community composition. MCMMMs achieved log₁₀ reductions of 5.47 ± 0.42 (Escherichia coli), 5.99 ± 0.46 (Saccharomyces cerevisiae), and 2.79 ± 0.31 (wastewater CFU); reductions by pure PES/PVP membranes were comparable: higher for Escherichia coli and wastewater CFUs, lower for Saccharomyces cerevisiae. Amplicon sequencing showed altered relative abundances in wastewater effluent. Collectively, these findings demonstrate the potential of MCMMMs to simultaneously remove microorganisms, extracellular DNA, and micropollutants, highlighting their suitability for water treatment applications within the One Health framework. Full article

This study investigates the development of mixed matrix membranes based on polyethersulfone incorporated with attapulgite for gas separation applications, addressing the existing gap regarding the use of this mineral in dense membranes obtained exclusively by solvent evaporation and its combined effects on microstructure and transport. The membranes were prepared by phase inversion via solvent evaporation, using solvent/polymer ratios of 75/25 and 80/20 and a thickness of 0.25 mm. The solutions were evaluated in terms of viscosity, and the membranes were characterized by structural techniques such as X-ray diffraction (XRD), atomic force microscope (AFM), contact angle, mechanical properties (tensile testing), and water vapor permeation. The results showed that attapulgite incorporation promoted a reduction in surface roughness (up to ~40%) and a decrease in contact angle (from ~89° to ~68°), indicating increased hydrophilicity. In addition, water vapor permeability was influenced in a non-linear manner, with optimized performance observed at 3 wt% filler loading. Solution viscosities remained within ranges suitable for processing. Structural analyses indicated compatibility between the phases, while morphology changes dependent on filler content were decisive for transport behavior. It is concluded that attapulgite is a promising additive for fine-tuning membrane properties, enabling optimization of the sorption–diffusion balance and improvement of membrane performance in separation applications. Full article

Articular cartilage has a limited capacity for self-repair, and effective strategies for its regeneration remain a major clinical challenge. Full-thickness cartilage defects extending to the subchondral bone induce an enhanced inflammatory response and impair spontaneous healing. This study aimed to evaluate the regenerative potential of autologous chondrocyte transplantation using an insoluble polyethersulfone (PES) scaffold in a rabbit model of grade III articular cartilage lesions. Chondrocytes were isolated and expanded in vitro and subsequently seeded onto PES membranes. Sixty-two rabbit knees with defects extending to the subchondral bone were divided into three groups: group I received chondrocyte-seeded PES scaffolds (n = 25), group II received cell-free PES scaffolds (n = 25), and group III served as an untreated control (n = 12). Cartilage regeneration was evaluated macroscopically and histologically over 52 weeks. In addition, the chondrogenic differentiation potential of cells cultured on PES scaffolds was assessed. This study extends our previous investigations of PES scaffolds in grade IV cartilage defects to a clinically relevant grade III lesion model, enabling evaluation of regenerative outcomes at an earlier stage of cartilage degeneration. The results demonstrated superior tissue regeneration in defects treated with chondrocyte-seeded PES scaffolds compared to both control groups. These findings indicate that synthetic PES scaffolds support cartilage repair and represent a promising biomaterial for the development of cell-based therapies in articular cartilage regeneration. Full article

Sulfonated aromatic polymers (SAPs) represent promising alternatives to perfluorinated ionomers for proton-exchange membrane fuel cells (PEMFCs), but their high hydrophilicity and limited chemical stability often require structural reinforcement and controlled cross-linking. In this study, composite membranes based on sulfonated poly(phenylsulfone) (SPPSU) and sulfonated poly(ethersulfone) (SPES) were fabricated with and without electrospun PPSU nanofiber mats and subsequently cross-linked through a solvent-induced sulfone-bridge formation at 180 °C. SPPSU/SPES blends (70/30, 50/50, 30/70) displayed good miscibility, while PPSU fibers improved dimensional stability and suppressed excessive swelling. Cross-linking strongly influenced membrane properties: intermediate treatment (20 h) enhanced mechanical strength and solvent resistance with limited loss of IEC, whereas extended treatment (30 h) produced highly stable, low-swelling networks. Despite lower IEC and water uptake, 30 h-treated membranes exhibited higher proton conductivity, attributed to reduced tortuosity and more continuous ionic pathways. Mechanical and hydration analyses identified SPPSU-50, SPPSU-70, and SPPSU-100 as the most balanced compositions. Proton mobility analysis revealed high membrane tortuosity, consistent with dense cross-linked structures reinforced by fibers. Overall, the combined use of SPPSU/SPES blending, PPSU nanofiber reinforcement, and sulfone-bridge cross-linking yields robust, water-insoluble membranes with improved electrochemical performance suitable for PEMFCs and other applications. Full article

Background: Online hemodiafiltration (HDF) represents the most advanced form of kidney replacement therapy, combining diffusive and convective transport to enhance the removal of uremic toxins across a wide molecular spectrum. Achieving high convective volumes is a key determinant of treatment efficacy and has been associated with improved survival. Beyond small solutes, HDF targets middle molecules and protein-bound uremic toxins (PBUTs), including β₂-microglobulin, inflammatory cytokines, and other large uremic compounds implicated in cardiovascular and systemic complications. Aims: This narrative review examines advances in dialysis membrane materials, dialyzer design, and monitoring technologies that optimize mass transfer in HDF. It focuses on the interplay between membrane permeability, hemocompatibility, and convective dose delivery, and discusses how these engineering developments translate into clinical performance. Key mechanisms: Recent progress in synthetic polymer membranes, particularly polysulfone- and polyethersulfone-based systems, and hollow-fiber manufacturing has enabled improved control of pore size distribution, hydraulic permeability, and sieving characteristics. These developments enhance the clearance of middle molecules and selected PBUTs while preserving essential proteins such as albumin. Mechanistic insights into internal filtration, protein polarization, and Donnan effects highlight the complex transport processes occurring within the dialyzer and their interaction with automated HDF systems. Expanded hemodialysis and high-volume HDF approaches further increase the removal of larger solutes but require careful management to limit albumin loss and maintain hemocompatibility. Clinical implications: Optimized membrane design, combined with advanced HDF machine algorithms, allows delivery of high convective volumes under safe and stable conditions, improving removal of β₂-microglobulin, cytokines, and other clinically relevant toxins associated with inflammation and cardiovascular risk. However, treatment must remain individualized, considering electrolyte balance, albumin preservation, and patient-specific factors such as inflammation and nutritional status. Mechanistic modeling supports understanding of transport phenomena but must be interpreted cautiously when translated into clinical practice. Conclusions: Advances in membrane science, dialyzer engineering, and monitoring technologies have strengthened the role of HDF as a precision-based renal replacement therapy. Continued innovation aimed at optimizing middle-molecule and PBUT clearance while preserving albumin and treatment stability is essential to improve patient outcomes and support the broader implementation of HDF as a mainstream dialysis modality. Full article

Investigation of dialyzer thrombogenicity is a critical step during the development of a new dialyzer. Novel dialyzer membranes aim to reduce the inherent thrombogenic potential of artificial surfaces by, e.g., increasing membrane hydrophilicity. Reliable in vitro testing is fundamental during dialyzer development and must be in line with the current standards. Using the novel FX CorAL dialyzer with its increased membrane hydrophilicity as an example, this study characterizes dialyzer thrombogenicity in an in vitro test setup in line with ISO 10993-4 and identifies factors which influence dialyzer thrombogenicity. In a recirculation setup with human blood, platelet activation (platelet counts, β-thromboglobulin, platelet adsorption), coagulation (thrombin–antithrombin III complex) and complement activation (sC5b-9) were investigated among polysulfone- (FX CorAL, FX CorDiax, Optiflux, xevonta), polyethersulfone- (ELISIO, Revaclear, Theranova) and AN69 ST-based (Nephral) dialyzers. Additionally, the impact of dialysate and electrolyte composition on thrombogenicity was investigated. The FX CorAL showed the lowest platelet activation compared to all poly(ether)sulfone-based dialyzers and lower complement activation compared to most poly(ether)sulfone-based dialyzers and to the Nephral dialyzer. No significant differences were observed between the investigated dialyzers with regard to plasmatic coagulation. Among the tested parameters, the dialyzer showed the strongest impact on the thrombogenicity results. This study proposes guidance on in vitro testing of dialyzer thrombogenicity in line with current standards and may contribute to reducing the current heterogeneity among in vitro hemocompatibility testing. Full article

To tailor surface chemistry and wettability for advanced membrane applications, this study investigates PES-, PES–PVP-, and PES–GO-based nanofiber membranes modified through oxygen plasma treatment. The plasma process introduced reactive functional groups, including SO₃H, C=O, and OH, onto the fiber surfaces, converting the membranes from hydrophobic to super-hydrophilic and enhancing their surface reactivity. This modification enabled tunable wettability, allowing controlled adjustment of the membrane’s hydrophilic behavior. Overall, the results demonstrate the effectiveness of plasma engineering in developing versatile nanofiber membranes with customizable surface properties for a wide range of applications. Full article

Clean water remains a pressing global challenge and developing membranes that are both efficient and durable is critical. This study combined two polymers, polyethersulfone (PES) and sulfone-modified polysulfone (SPSf), with NiFe-layered double hydroxides (LDHs) to create a new class of multifunctional membranes. The membranes were characterized using FTIR, SEM, water contact angle, and zeta potential. The addition of NiFe-LDH fillers improved the hydrophilicity and surface structure of the membranes and enhanced the separation performance of the resulting membranes. The best-performing membrane (M3, with 2 wt.% NiFe-LDH) delivered pure water flux of about 218 L.m⁻²h⁻¹, which was nearly three times higher than that of the pristine PES/SPSf membrane. Furthermore, M3 removed approximately 92.4% of bovine serum albumin (BSA), attributed to the synergistic combination of size exclusion, electrostatic repulsion, and hydrophilicity. The membrane also showed excellent antifouling properties, maintaining over 65.9% and 71.2% flux recovery after three fouling–cleaning cycles for BSA solution and surface water, respectively. Importantly, the M3 membrane achieved high removal efficiencies for heavy metals, rejecting 91% of Cd²⁺, 93% of Pb²⁺, and 88% of Cu²⁺. These results highlight how the synergy between PES/SPSf and NiFe-LDH can overcome the common challenges of fouling and low metal ion rejection, offering a promising route toward practical and sustainable water treatment solutions. Full article

In this study, we aimed to develop a high-performance, anti-fouling ultrafiltration membrane by integrating photocatalytic and Fenton-like functions into a polymer matrix, in order to address the critical challenge of membrane fouling and achieve simultaneous separation and degradation of organic pollutants. To this end, a novel Fe-V_O-TiO₂-embedded polyethersulfone (PES) composite membrane was designed and fabricated using a facile phase inversion method. The key innovation lies in the incorporation of Fe-V_O-TiO₂ nanoparticles containing abundant bulk-phase single-electron-trapped oxygen vacancies, which not only modulate membrane morphology and hydrophilicity but also enable sustained generation of reactive oxygen species for the pollutant degradation under light irradiation and H₂O₂. The optimized Fe-V_O-TiO₂-PES-0.04 membrane exhibited a significantly enhanced pure water flux of 222.6 L·m⁻²·h⁻¹ (2.2 times higher than the pure PES membrane) while maintaining a high bovine serum albumin (BSA) retention of 93% and an improved hydrophilic surface. More importantly, the membrane demonstrated efficient and stable synergistic Photocatalytic-Fenton activity, achieving 82% degradation of norfloxacin (NOR) and retaining 75% efficiency after eight consecutive cycles. A key finding is the membrane’s Photocatalytic-Fenton-assisted self-cleaning capability, with an 80% flux recovery after methylene blue (MB) fouling, which was attributed to in situ reactive oxygen species (·OH) generation (verified by ESR). This work provides a feasible strategy for designing multifunctional membranes with enhanced antifouling performance and extended service life through built-in catalytic self-cleaning. Full article

Heavy metals released from industrial effluents accumulate in the human body through the ecosystem, causing several health disorders. This study investigated the removal of cadmium (Cd²⁺) using Micellar-Enhanced Ultrafiltration (MEUF). This study employed sodium dodecyl sulfate (SDS) and flat-sheet polyethersulfone (PES) ultrafiltration membranes to separate Cd²⁺ ions from lab-simulated water. The experiments involved examining the removal efficiency of membranes without SDS usage, optimizing SDS concentration for Cd²⁺ removal, and evaluating the long-term membrane performance. Other parameters include analyzing the removal percentage of varying Cd²⁺ at constant SDS dosage, examining the effect of pH, and electrolyte concentrations on the removal of Cd²⁺. Several analytical characterizations were performed, such as FT-IR, and SEM. The FTIR confirms the aromatic C-H group at 620–867 cm⁻¹, the sulfone group at 1100–1200 cm⁻¹, and the ether group at 1230–1270 cm⁻¹ and the SEM analysis indicates no significant fouling, which aligns with the stable flux observed over time. The result showed that the optimum SDS concentration for Cd²⁺ removal was 1 Critical Micellar Concentration (CMC), achieving over 99% removal. The presence of an electrolyte decreased Cd²⁺ removal efficiency, while the pH (3 to 9) had no effect on removal. Our findings suggest that the SDS-aided ultrafiltration process is suitable for eliminating Cd²⁺ from wastewater. Full article