Membranes最新文献

The ultimate objective of this research is to concentrate nutrients-nitrogen (N), phosphorus (P), and potassium (K)-and produce process water from a chemically pretreated liquid digestate using an FO-RO hybrid process. However, in this manuscript, we assessed the suitability of (NH₄)₂SO₄ and NaCl as draw solutes in a series of FO experiments employing a commercial CTA membrane and DI water as the feed solution. We also examined the regeneration of (NH₄)₂SO₄ in a series of RO experiments at various feed concentrations and pressures using a commercial polyamide (PA) thin-film composite (TFC) membrane, ACM4. Additionally, the RO experiments enabled the experimental determination of the osmotic pressure of (NH₄)₂SO₄ at various feed concentrations, which is crucial for designing the FO part of the hybrid process. The CTA membrane exhibited a significantly greater selectivity for (NH₄)₂SO₄ than for NaCl at any osmotic pressure. The RO experiments demonstrated the possibility of reconcentrating (NH₄)₂SO₄ to 0.5 mol/L, with a corresponding water flux of 60 L h^-1 m^-2 at 40 bars. The experimentally determined osmotic pressures were lower than those predicted by van't Hoff's equation but were consistent with those reported in the literature using an indirect hygrometric method.

MXenes, members of two-dimensional materials, were discovered in 2011 for the first time. MXenes are famous nowadays for their attractive and unique properties such as hydrophilicity, surface area, and catalytic activity for various industrial applications. This review comprehensively focused on composite membranes with MXenes that can be directly deployed for water purification. Moreover, this review will also give significant insight into new synthetic approaches for MXene-based composite membranes. A review of the utilization of MXene-based composite membranes in modern separation techniques such as nanofiltration, ultrafiltration, and forward osmosis has also been summarized. Finally, the current issues and future perspectives on applying two-dimensional materials for water treatment are elaborately discussed.

A commercial anion-exchange membrane was modified via the electrodeposition of different water-soluble polymers to study the effects of surface modification on electrodialysis performance. X-ray photoelectron spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy analyses showed that the different polymers were successfully electrodeposited on the membrane surface. The surface morphology and electrical resistance of the modified AEMs were almost unchanged. Contact angle and zeta potential measurements indicated differences in the surface hydrophilicity and surface charge density of the modified AEMs. The electrodialysis performance of the pristine AEM declined significantly in the presence of the foulant. In contrast, the electrodialysis performance of the AEMs modified with poly (vinylsulfonic acid, sodium salt) showed almost no decline and exhibited the best antifouling property in the presence of the foulant, followed by those modified with poly (sodium acrylate) and poly (vinyl alcohol). The results indicated that an increase in surface negative charge density and surface hydrophilicity increased the resistance of the modified AEMs to the foulant and improved their electrodialysis performance.

Efficient management for electrochemical reactions within Pt/C electrodes, specifically the oxygen reduction reaction (ORR) and methanol oxidation reactions (MOR), is critical to the performance and long-life stability of direct methanol fuel cells (DMFCs). Optimizing the hierarchical macro/mesoscale structures of Pt/C electrodes plays a decisive role in regulating the mass transport pathways and electrochemical reactions. In this work, bead-like Pt/C-ionomer hybrid porous nanofibrous networks are constructed via electrospinning. Ascribing to the hierarchical architecture consisting of continuous nanofibers and bead-like Pt/C-ionomer fibrous networks, the hybrid porous nanofibrous electrode exhibits a 55% increase in maximum mass power density in comparison to the conventional Pt/C electrode. Such enhancement is attributed to excellent ORR activity enabled by efficient triple-phase reaction regions, coupled with superior MOR tolerance resulting from restricted methanol transport from the hybrid porous nanofibrous electrode to triple-phase reaction regions.

This study reports the development of an optimized tight ultrafiltration (UF) membrane prepared from recycled acrylic fiber (polyacrylonitrile, PAN) waste for the efficient removal of organic pollutants from water. Membranes were fabricated using different concentrations of acrylic fiber waste to examine the influence of polymer content on their morphology and performance. The prepared membranes were characterized using scanning electron microscopy (SEM), porosity measurements, contact angle analysis, and mechanical strength testing to evaluate their structural and physicochemical properties. Among the tested formulations, membrane M4, containing 22.5 wt.% acrylic fiber waste, shows the most balanced performance, high mechanical integrity, and good surface hydrophilicity, with a contact angle of about 52° and porosity of 27%. The optimized M4 membrane demonstrates excellent pure water flux of 65 LMH. M4 achieves a flux recovery ratio (FRR) above 80%. Its performance was further evaluated for the removal of humic acid (HA) and paracetamol as a model of organic contaminants. The results also demonstrate strong chemical stability under acidic and basic conditions, highlighting the potential of recycled acrylic fiber waste as a sustainable polymer source for high-performance tight UF membranes. This approach offers an environmentally friendly and cost-effective solution for water purification and pharmaceutical contaminant removal.

The separator is a key component of lithium-ion batteries, and its properties play a crucial role in the performance of such batteries. However, the most widely used polyolefin separators are not only made from non-renewable resources such as petroleum, but also have poor wettability to electrolytes, and their low melting points may cause short circuits or even explosions. Therefore, advanced separators that meet the increasing requirements of such batteries are urgently needed. Compared to polyolefin separators, renewable biomass fiber-based separators have better compatibility with electrolytes, higher thermal stability, and are naturally abundant. Their use is not only in line with sustainable development, but it also lowers their material cost. Therefore, biomass fiber-based separators are considered a promising candidate for replacing polyolefin separators for lithium-ion batteries in the future. In this article, studies on the preparation and application of biomass fiber-based separators in lithium-ion batteries in recent years are reviewed, looking forward to their future development, with the aim of providing a reference for researchers.

Polysulfone (PSF), despite its excellent thermal and mechanical stability, exhibits moderate gas separation performance and poor compatibility with inorganic fillers, resulting in interfacial voids and structural defects. This study addressed these limitations by incorporating vinyltrimethoxysilane (VTMS)-functionalized TiO₂ nanoparticles into PSF matrix to develop mixed matrix membranes (MMMs) for selective CO₂/N₂ separation. Membranes with 1-5 wt.% VTMS@TiO₂ loadings were fabricated via solution casting, and their gas separation performance was systematically evaluated. VTMS modification enhanced the dispersion and interfacial adhesion of TiO₂ within the PSF matrix, as confirmed by SEM, FTIR, XRD, and TGA analyses. The 4 wt.% VTMS@TiO₂ loaded membrane showed optimal performance, with a CO₂ permeability of 8.48 barrer and a CO₂/N₂ selectivity of 26.50 due to stronger polymer-filler interactions and enhanced CO₂ affinity by VTMS functional groups. This membrane has shown stable transport behavior and favorable CO₂ selectivity as confirmed by pressure- and temperature-dependent permeation studies. Robeson plot analysis showed that the optimized membrane approached the upper bound, demonstrating a significant improvement over pure PSF. The study confirmed that VTMS-functionalized TiO₂ enhanced both permeability and selectivity through improved filler dispersion, interfacial integrity, and CO₂ affinity.

Pharmaceutically active compounds (PhACs), pesticides, and poly- and perfluoroalkyl substances (PFAS) are increasingly detected in surface waters at trace concentrations, raising concerns for both aquatic systems and, consequently, human health. Conventional solutions are insufficient to achieve complete removal at trace compound concentrations, highlighting the need for advanced separation technologies. This study aims to comprehensively analyze rejection and removal mechanisms of selected PhACs, pesticides, and PFAS present in water solutions at reported environmentally relevant concentrations (300 ng L^-1), using two nanofiltration (NF) and one reverse osmosis (RO) polyamide membrane. PhACs, pesticides, and PFAS were selected to cover a broad range of physicochemical properties, specifically molecular mass (MM), dissociation constant (pKa), and octanol-water partition coefficient (logK_o/w). Rejection values ranged from 42.1% (acetaminophen) to apparent 100% (for multiple compounds), depending on water pH, solute properties, and membrane characteristics. Size exclusion and electrostatic interactions were identified as the primary removal mechanisms, with hydrophobic interactions having a lower impact, particularly for carbamazepine, bezafibrate, and perfluorooctane sulfonic acid (PFOS). Addition of sodium chloride (3 g L^-1) decreased rejection of most negatively charged compounds due to suppression of membrane surface charge, although clarithromycin and ofloxacin exhibited improved rejection. Presented results provide fundamental insight into compound-specific membrane rejection and highlight the importance of membrane-solute interactions under environmentally realistic conditions. The results support further optimization of NF and RO for targeted compound rejection and provide a baseline for data-driven membrane process modeling.

Interrelations between the plasma membrane and cytoskeleton are of crucial importance for essential cellular processes such as endocytosis, formation of intercellular junctions, cell morphology, etc. Many studies validate the beneficial effects of polyphenols as antioxidant and protective agents, but a molecular mechanism of their interaction and transition through the plasma membranes of different cell lines is still missing. In this study, we examined the affinity of fractions enriched in flavonoid glycosides (FGs) and caffeoylquinic acids (CQAs), obtained from the methanol extract of the medicinal plant Inula oculus-christi L., to reorganize the plasma membrane structure and actin cytoskeleton by using confocal microscopy. Assessment of the degree of membrane ordering aiming to distinguish the ordered from disordered regions of the cellular membranes was performed using the fluorescent dye Di-4-ANEPPDHQ, and visualization of F-actin was by TRITC-phalloidin. Two epithelial cell lines with clear differences in their origin and plasma membrane organization were chosen: the non-malignant MDCK II and the cancerous A549. Our results showed that flavonoid glycosides exhibited an ordering effect on plasma membranes of cancerous cells and fluidized one on non-malignant cells. Different patterns of actin reorganization were observed for both cell lines after treatment. Our results indicate the potential of plant-derived polyphenols as modulators of the membrane's structural organization, offering valuable insights for the development of membrane-targeted therapeutic strategies.

Optimizing the MEA structure is crucial for enhancing the performance of open-cathode PEMFCs under water shortage conditions. By investigating the impact of gradient ambient temperature on performance, it is highlighted that cathode catalyst layer hydration deeply affects proton conduction in the membrane and three-phase boundary formation. These issues consequently increase ohmic resistance and cathode activation resistance as seen via polarization curve comparison and the electrochemical impedance spectroscopy analysis method, ultimately degrading overall stack voltage output under the same current density. Under indoor temperature and humidity conditions, an orthogonal experiment was designed to validate the sensitivity analysis on the cathode I/C ratio (0.74-0.9) and catalyst layer thickness (8, 12 μm) by controlling the catalyst-coated membrane manufacture process; GDL thickness (185-324 μm) and pore structure were also investigated, combining parameter characterization techniques like MIP and BET. It is shown that with an I/C ratio of 0.86, a medium GDL pore structure and a higher catalyst layer thickness of 12 μm bring better performance output, especially when the OC PEMFC is 700 mA/cm² @ 0.62 V.