Membranes最新文献

To mitigate the risks associated with production wastewater from water treatment plants, this study evaluated the effectiveness of nanofiltration (NF) and a hybrid ceramic membrane-nanofiltration (CM-NF) process in removing natural organic matter (NOM) and Ca²⁺. A comprehensive analysis of changes in specific flux and fouling resistance of the NF membrane, combined with scanning electron microscopy (SEM) observations, provided deeper insight into membrane fouling behavior. The results show that the CM-NF process achieved average removal rates of 95.60% for DOC, 98.55% for UV₂₅₄, 34.50% for conductivity, and 50.71% for Ca²⁺. These values represent improvements of 4.70%, 1.40%, 16.37%, and 10.36%, respectively, compared to the standalone NF process. Furthermore, CM pretreatment consistently optimized the performance of the nanofiltration system. After continuous operation, the average specific membrane flux of the CM-NF system reached 0.715, 0.67, and 0.61 under varying pollutant concentrations-increases of 10.9%, 19.6%, and 17.3% over the standalone NF system-confirming a significant improvement in permeate flux. Under continuous operation, the average degree of irreversible fouling was markedly reduced across different pollutant concentrations-decreasing from 9.2%, 17.6%, and 23.6% for the standalone NF system to 8.9%, 15.6%, and 10.9% for the CM-NF system, which clearly demonstrates the efficacy of CM pretreatment in controlling irreversible fouling. SEM observations further corroborated that CM pretreatment effectively alleviated fouling on the NF membrane surface. Additionally, higher Ca²⁺ concentrations were found to contribute to reduced membrane fouling and enhance flux performance.

To address the issues of hydrophobicity, easy fouling, and limited application of polyvinylidene fluoride (PVDF) membranes in water treatment processes, this study prepared Cu-MnO₂/GO/PVDF catalytic membranes via the immersion precipitation phase inversion method. Graphene oxide (GO) was incorporated to facilitate the construction of good water channels, while copper-doped manganese dioxide (Cu-MnO₂) was added to enhance catalytic activity. The structure, morphology, and performance of the membranes were characterized comprehensively. Results showed that Cu-MnO₂ was well interspersed between GO sheets, thereby increasing membrane surface roughness, effective filtration area, and hydrophilicity. The best catalytic membrane CM-5 exhibited the highest pure water flux (1391.20 L·m^-2·h^-1) and methyl blue (MBE) rejection rate (98.06%), and it also displayed excellent reusability and stability. EPR tests confirmed the generation of HO· and HOO· in the Fenton-like system, which mediated dye degradation. The Cu-MnO₂/GO/PVDF catalytic membrane demonstrated excellent hydrophilicity, antifouling properties, and catalytic efficiency, thus providing a viable solution for dye wastewater treatment.

Polydimethylsiloxane (PDMS) is commonly used in gas-separation studies because of its high CO₂ permeability and stable mechanical properties. In this work, mixed matrix membranes (MMMs) were prepared by incorporating the bimetallic MOFs Ni-Cu-MOF-74, Ni-Co-MOF-74, and Ni-Zn-MOF-74 into a PDMS matrix. The membranes were fabricated by solution casting and characterized by SEM, XRD, FT-IR, and BET analyses, which confirmed uniform filler dispersion and the successful incorporation of the MOF-74 structures. Single-gas permeation tests showed clear performance improvements with MOF loading. The best results were obtained for the membrane containing 1 wt.% Ni-Cu-MOF-74, which reached a CO₂ permeability of 3188.25 Barrer and a CO₂/N₂ selectivity of 35.10. The improvement is attributed to the accessible metal sites and high surface area provided by the MOF-74 framework, which enhanced adsorption-diffusion pathways for CO₂ transport. These results show that PDMS/MOF-74 mixed-matrix membranes are effective for CO₂/N₂ separation, with Ni-Cu-MOF-74 achieving the highest performance.

This research focuses on developing and optimizing mixed matrix membranes (MMMs) by incorporating graphene oxide (GO) into a polysulfone (PSF) matrix to enhance the separation performance of CO₂ and CH₄. The morphology and gas separation performance of the MMMs were systematically characterized. The incorporation of GO enhanced gas permeation and CO₂/CH₄ selectivity, as evaluated using a gas permeation setup. Notably, the PSF/GO-0.3 wt.% membrane exhibited superior performance, achieving a CO₂ permeability of 21.63 Barrer, among the highest reported for PSF-based MMMs. Additionally, the membrane demonstrated a CO₂/CH₄ selectivity of 14.32, highlighting its effectiveness in distinguishing between the two gases, which is essential for carbon capture and natural gas decontamination applications. The uniform distribution of GO within the polymer matrix contributed to the membrane's enhanced performance. Furthermore, the MMMs exhibited outstanding resistance to CO₂ plasticization, with the PSF/GO-0.3 wt.% membrane maintaining its performance at pressures up to 10 bar, a significant improvement over the pristine PSF membrane, which failed at 4 bar. The improved plasticization resistance is ascribed to the reinforcing effect of GO, which stabilizes the polymer matrix, minimizing CO₂-induced swelling. The PSF/GO-0.3 wt.% membrane exhibited exceptional CO₂ permeability, selectivity, and plasticization resistance, making it a viable alternative for industrial gas separation applications and outperforming previously reported PSF-based MMMs.

While there is a consensus that the cytochrome b₆f complex (cytb₆f) in algae and plants is involved in the regulatory mechanism of oxygenic photosynthesis known as light-induced state transitions (STs), no such consensus exists for cyanobacteria. Here, we provide the first direct functional evidence for cytb₆f using single-point mutation data. We introduced a PetD-Phe124Ala substitution in the cyanobacterium Synechocystis sp. PCC 6803 to test the key predictions of the hydrophobic-mismatch (HMM) model for cytb₆f-driven STs in all oxygenic photosynthetic species. These predictions concern the role of the Phe/Tyr124^fg-loop-PetD and the extent and kinetic characteristics of STs. The effects of PetD-F124A mutation on STs were monitored using 77K and Pulse-Amplitude-Modulated (PAM) fluorescence. For comparison, we employed a phycobilisome (PBS)-less Synechocystis mutant and wild-type (WT) strain, as well as the stn7 mutant and WT of Arabidopsis plant. The PetD-F124A mutation reduced the extent of STs and selectively affected the two-exponential kinetics components of the transitions. Under State 1 conditions, the mutant exhibited ~60% less energetic decoupling of PBS from photosystem I (PSI) compared to the WT. It is explainable by the HMM model with the inability of the PetD-F124A mutant, during the induction phase of the State 2→State 1 transition to adopt the cytb₆f conformation with minimal hydrophobic thickness. PAM-derived parameters indicated that PSII electron transport function is not inhibited, and no detectable effect on cyclic electron transport around PSI was observed under low-light conditions. Circular dichroism and differential scanning calorimetry confirmed that both the PSI trimer/monomer ratio and the structural integrity of the PBSs are preserved in the mutant. The compensatory response to the mutation includes decreased PSI content and an increase in PBS rod size. In conclusion, (1) cytb₆f is involved in cyanobacterial STs; (2) evidence is provided supporting the HMM model; (3) the electron transfer and signal transduction functions of cytb₆f are separated into distinct domains; and (4) the signaling pathway regulating STs and pigment-protein composition in Synechocystis involves PetD-Phe124.

Lipid-based nanomedicines are already widely used in antitumor therapy and gene delivery. However, their complex structural features demand advanced mesoscopic structural characterization tools for effective research and development (R&D) and quality control. Synchrotron small-angle X-ray scattering (SAXS) is a powerful, non-invasive technique for probing nanoscale membrane organizations, monitoring in situ dynamic membrane assembly, and exploring the interactions of components in lipid-based drug delivery systems, including liposomes, lipoplexes, lipid nanoparticles (LNPs), and lyotropic liquid crystals (LLCs). Recent advances in high-flux synchrotron facilities, high-frequency detectors, and automated SAXS data processing pipelines permit a detailed structural characterization of lamellarity, bilayer spacing, internal phases, core-shell morphology, as well as "pump-probe" dynamic process studies for lipid nanomedicines. Though major challenges remain in sample polydispersity and model fitting, the advances in time-resolved synchrotron SAXS, high-throughput automation, and artificial intelligence (AI)-assisted modeling are rapidly reducing this barrier. This review summarizes SAXS methodology and introduces representative case studies in the field of lipid nanomedicines. The performance of BioSAXS beamline BL19U2 in the Shanghai synchrotron radiation facility (SSRF) and prospects of AI-guided drug screening at BL19U2 are highlighted to advance intelligent R&D and quality control for lipid nanomedicines.

This article presents a conceptual perspective proposing that hypoxia acts as a unifying regulator of plasma membrane phosphohydrolases. We propose that oxygen sensing at the cell surface integrates adenosine and phosphate metabolism to sustain tumour adaptation. Within the oxygen- and nutrient-deprived tumour microenvironment, inorganic phosphate (Pi) and adenosine function as metabolic substrates and signalling mediators that promote cell proliferation, survival, and immune evasion. Stabilisation of hypoxia-inducible factor-1α (HIF-1α) enhances the expression and catalytic activity of specific phosphohydrolases, notably the ectonucleotidases CD39 (NTPDase1) and CD73 (ecto-5'-nucleotidase), which drive adenosine accumulation and immunosuppression. Conversely, the activity of transmembrane prostatic acid phosphatase (TM-PAP), responsible for hydrolysing phosphate esters such as p-nitrophenylphosphate (pNPP) and AMP, is inhibited under hypoxia through oxidative and kinase-dependent mechanisms. Collectively, these mechanisms characterise the plasma membrane as a dynamic metabolic interface, where oxygen sensing coordinates adenosine and phosphate turnover, thereby promoting tumour adaptation across hypoxic environments. We propose that hypoxia orchestrates a dual regulatory loop connecting adenosine accumulation and phosphate turnover at the tumour cell surface, providing a conceptual basis for future mechanistic studies.

Today, reducing carbon footprints requires the development of technologies to utilize CO₂, particularly by converting it into valuable chemical products. One approach is plasma-catalytic CO₂ splitting into CO and O₂. The task of separating such a ternary mixture is nontrivial and requires the development of an efficient method. In this paper, we have developed a comprehensive scheme for the separation of a CO₂/CO/O₂ mixture using membrane technology. The novelty of this work lies in the development of a complete scheme for separating the products of plasma-chemical decomposition of CO₂ to produce a CO concentrate. The calculations utilized the principle of a reasonable balance between the recovery rate and the energy consumption of the separation process. This scheme allows production of a CO stream with a purity of 99%. To achieve this goal, we have proposed the sequential use of CO₂-selective membranes based on polysiloxane with oligoethyleneoxide side groups (M-PEG), followed by polysulfone (PSF) hollow-fiber membranes to separate CO and O₂. For these membranes, we measured the CO permeability for the first time and obtained the selectivity for CO₂/CO and O₂/CO. The potential of membrane separation was demonstrated through a three-stage process, which includes recycling of the CO removal stream and concentration after CO₂ plasmolysis. This process was calculated to yield a highly pure CO stream containing 99 mol% with a recovery rate of 47.9-69.4%. The specific energy consumption for the separation process was 30.31-0.83 kWh per 1 m³ of feed mixture, and the required membrane area was between 0.1 m² for M-PEG and 42.5-107 m² for PSF, respectively.

The present study investigates the use of aluminum foam to enhance pure water production using a Vacuum Membrane Distillation (VMD) desalination unit. Numerical simulations were conducted for a conventional VMD and three VMD configurations with different metal foam thickness-to-channel-width ratios of h/b = (0.5, 0.75, 1). The effects of operational parameters on different VMD setups were presented and discussed. Additionally, the effects of flow rates on temperature polarization, average Nusselt number, and pressure drop were presented and discussed. The performance evaluation criterion (PEC), an indicator of the system's global performance encompassing the heat transfer enhancement and the related pressure loss, has also been used and analyzed. Outcomes demonstrate improvements in water production with the increase in inlet velocity and temperature, while applied vacuum pressure and inlet concentration increments showed opposite behavior for all studied VMD setups. Permeate flux and temperature polarization were enhanced with metal foam insertion, and the case h = b presents the highest permeate flux and pressure drop. PEC demonstrates values superior to unity for all studied cases, with higher values for lower flow rates. Fully filled metal foam insertion is recommended for lower flow rates, while partially filled metal foam (h = 0.5b) is suggested for higher ones.

In recent decades, rotating dynamic filtration (RDF) has attracted considerable attention due to its high efficiency and low energy consumption. While most studies have focused on separation behavior and membrane fouling, energy consumption in RDF has received limited attention. This study investigates the specific energy consumption (SEC) of the RDF process for ship exhaust gas cleaning (EGC) desulfurization wastewater treatment and proposes an optimization method based on both energy consumption and equipment cost. The total SEC increases with rotational velocity, circulation flow, feed concentration, and membrane size but decreases with temperature and remains unaffected by the number of membrane elements. In RDF, the total SEC is only 9.05-19.29% of that in tubular cross-flow filtration (CFF) at equivalent shear force ranging from 3.86 Pa to 121.14 Pa. Operating energy and investment costs are primarily determined by the number of membrane elements and the rotational velocity. According to the economic analysis, the lowest treatment cost for EGC wastewater is CNY 6.09 per cubic meter for a 5 m³·h^-1 capacity, using 84 membrane elements (374 mm, 0.2 µm) at a rotational velocity of 200 rpm, an operating pressure of 200 kPa, and a temperature of 40 °C.