Search Results (2,366)

Membrane fouling reduces permeate flux and treatment efficiency, yet most diagnostic methods are destructive and require offline analysis. Optical coherence tomography (OCT) enables in situ, real-time visualization; however, quantitative image extraction of thin foulant layers is often limited by manual processing and subjective thresholding. Here, we develop a reproducible OCT image-analysis workflow that combines band-pass filtering, Gaussian smoothing, and unsharp masking with a dual-threshold subtraction strategy for automated fouling-layer segmentation. Seventeen global thresholding algorithms in ImageJ (289 threshold pairs) were benchmarked against SEM-measured cake thickness, identifying Triangle–Moments as the most robust combination. For humic-acid fouling, the OCT-derived endpoint thickness (14.23 ± 1.18 µm) closely agreed with SEM (15.29 ± 1.54 µm). The method was then applied to other microfiltration foulants, including kaolin and sodium alginate, to quantify thickness evolution alongside flux decline. OCT with the optimized image analysis captured rapid early deposition and revealed periods where flux loss continued despite minimal additional thickness growth, consistent with changes in layer permeability and compaction. The proposed framework advances OCT from qualitative visualization to quantitative, real-time fouling diagnostics and supports mechanistic interpretation and improved operational control of membrane systems. Full article

Polymeric microfiltration membranes are among the most utilized pressure-driven membranes due to their excellent permeation flux, moderate removal efficiency, low operating pressure, low cost, as well as their potential for reusability and cleanability. Therefore, these membranes are used in different crucial sectors, including the water and wastewater, dairy, beverage, and pharmaceutical industries. However, well-known polymeric microfiltration membranes suffer from their poor hydrophilic properties, causing fouling phenomenon. A reduction in permeate flux, a shortened operational lifespan, and increased energy consumption are the primary negative consequences of membrane fouling. Over the years, a broad spectrum of studies has been performed to modify polymeric microfiltration membranes to improve their hydrophilic, transport, and antifouling characteristics. Despite extensive research, this issue remains a subject of ongoing discussion and scrutiny within the scientific community. This review article provides promising information about different physical and chemical modification methods—such as polymer blending, the incorporation of nanomaterials, surface coating, chemical crosslinking, in situ nanoparticle immobilization, and chemical surface functionalization—for polymeric microfiltration membranes. The physical and chemical modification methods are comparatively evaluated, highlighting their positive and negative aspects, supported by findings from recent investigations. Moreover, promising ideas and future-oriented techniques were proposed to obtain polymeric microfiltration membranes containing superior efficiency, extended service life, and mechanical strength. Full article

A new method of in situ hydrothermal reduction of graphene oxide (GO) to reduced graphene oxide (rGO) in polymer bulk was developed, which involves heating GO/polyacrylonitrile (PAN) composite membranes (0.5; 1.0; 2.0% w/w of GO/PAN) in the presence of water vapor at a temperature of 120 °C and a pressure of 0.2 MPa. As a result of this process, membranes containing rGO were obtained, as confirmed by FTIR, Raman, WAXS and TGA studies. The composite membranes obtained after hydrothermal reduction of GO to rGO (B60, C60, D60) were substantially different from the initial membranes containing unreduced GO (B0, C0, D0). The hydrothermal reduction process clearly influenced the physicochemical properties (reduction of apparent density, water sorption, and increase in the contact angle) and transport properties of the B60, C60, and D60 membranes (decrease in water flux by ~104 [dm³/m² × h] and even ~348 [dm³/m² × h] compared to the initial membranes). Full article

This study evaluates the partial dealcoholization of red wine using reverse osmosis (ACM3) and nanofiltration (TS80) membranes at 25 and 35 bar, targeting 2% and 4% ethanol reductions. Membrane performance was assessed through fouling analysis and ethanol partitioning, while wine phenolic (flavan-3-ols, anthocyanins) and color characteristics (CIELab parameters) were determined. The 2% reduction process with ACM3 at 25 bar resulted in minimal phenolic changes. The 4% reduction process revealed distinct performance profiles: ACM3 exhibited exceptional stability (3.35–5.30% permeability loss, linear flux decline with R² > 0.93) and ethanol rejection of 17.6–25.5%, while TS80 achieved processing rates three to six times faster with moderate fouling (16.3% loss, 7.7–13.3% rejection). Decreases in flavan-3-ols and anthocyanin concentrations correlated with fouling intensity rather than processing duration. Proanthocyanidin structure remained stable, and color shifts reflected changes in polymeric pigments rather than anthocyanin loss. Reverse osmosis at low transmembrane pressure proved most suitable for quality preservation. The operational trade-off is clear: TS80 offers three to six times faster processing but with greater phenolic loss, while ACM3 requires longer batch times with minimal fouling. Both processes demonstrate that membrane-based dealcoholization without fluid replacement is feasible, providing winemakers with a valuable method to reduce alcohol while preserving quality. Full article

Photocatalytic reduction of CO₂ into value-added chemicals offers a sustainable route to mitigate greenhouse gas emissions while producing renewable fuels. However, conventional TiO₂-based systems suffer from limited visible-light activity and inefficient reactor configurations. Here, we developed electrospun polyacrylonitrile (PAN) membranes embedded with TiO₂-Cu₂O heterojunction nanoparticles and integrated them into a custom crossflow photocatalytic membrane reactor. The reactor employed bifacial illumination using a solar simulator (front) and a xenon/mercury lamp (back), each calibrated to 1 Sun (100 mW·cm⁻²). Membrane morphology was characterized by SEM, and chemical composition was confirmed by XPS. Photocatalytic performance was evaluated in CO₂-saturated 0.5 M potassium bicarbonate solution under continuous flow. The PAN/ TiO₂-Cu₂O membrane exhibited a methanol production rate of approximately 300 μmol·g⁻¹·h⁻¹ under dual-light illumination, outperforming single illumination, PAN-TiO₂, and PAN controls. Enhanced activity is attributed to extended visible-light absorption, improved charge separation at the TiO₂-Cu₂O heterojunction, and optimized photon flux through bifacial illumination. The electrospun architecture provided high surface area and porosity, facilitating CO₂ adsorption and catalyst dispersion. Combining heterojunction engineering with bifacial reactor design significantly improves solar-driven CO₂ conversion. This approach offers a scalable pathway for integrating photocatalysis and membrane technology into sustainable fuel synthesis. Full article

An organophilic composite membrane, ZIF-67@PDMS, was fabricated to enhance the isolation of natural aromatic compounds. The as-prepared composite membrane was characterized using SEM, EDS, FTIR, XRD, and contact angle measurement. In comparison to pure PDMS, ZIF-67@PDMS, featuring a loading capacity of 2.5 wt% of PDMS and a membrane thickness of 15 μm, demonstrated markedly improved separation performance for the characteristic aroma compounds of strawberries, namely linalool, benzaldehyde, and ethyl acetate. Under optimal conditions, the permeation fluxes of the three compounds were 628.02 mg∙m⁻²∙h⁻¹, 294.82 mg∙m⁻²∙h⁻¹, and 254.14 mg∙m⁻²∙h⁻¹, along with separation factors of 26.48, 7.94, and 6.32, respectively. ZIF-67@PDMS was then employed to isolate aromatic compounds from freshly squeezed strawberry juice. By backfilling the permeate, both the variety and the content of aromatic compounds in strawberry concentrate were notably restored, and its aroma profile also closely resembled that of fresh strawberry juice. Full article

The endolysosomal system plays a pivotal role in cellular function. Before reaching lysosomes for degradation, the endocytosed cargoes are sorted at various stages of endosomal trafficking for recycling and/or rerouting. The proper execution of these processes depends on tightly regulated ion fluxes across endolysosomal membranes. Recent studies have demonstrated the importance of two-pore channels (TPCs), including TPC1 and TPC2, in endolysosomal trafficking. These channels are expressed in the membranes of distinct populations of endosomes and lysosomes, where they respond to nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P₂] to conduct Ca²⁺ and Na⁺ release from these acidic organelles. Here, we discuss the potential implications of Ca²⁺ and Na⁺ fluxes mediated by TPCs across endolysosomal membranes in the physiological and pathophysiological functions of these organellar channels. 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

Recycling water offers a powerful way to lower the environmental water impact of mining activities. Pressure-retarded osmosis (PRO) represents a promising pathway for simultaneous water reuse and clean energy generation from salinity gradients. In this study, the performance of a thin-film nanocomposite (TFN) membrane containing functionalized multi-walled carbon nanotubes (fMWCNTs) within a polyacrylonitrile (PAN) support layer, followed by polydopamine (PDA) surface modification, was investigated under a PRO operation using pretreated gold mining wastewater as the feed solution. Unlike most previous studies that rely on synthetic feeds, this work evaluates the membrane performance under a PRO operation using a real mining wastewater stream. The membrane with fMWCNTs and PDA exhibited a maximum power density of 25.22 W/m² at 12 bar, representing performance improvements of 23% and 68% compared with the pristine thin-film composite (TFC) and commercial cellulose triacetate (CTA) membranes, respectively. A high water flux of 75.6 L·m⁻²·h⁻¹ was also obtained, attributed to enhanced membrane hydrophilicity and reduced internal concentration polarization. The optimized membrane, containing 0.3 wt% fMWCNTs in the support layer and a PDA coating on the active layer, produced a synergistic enhancement in the PRO performance, resulting in a lower reverse salt flux and an improved flux–selectivity trade-off. Furthermore, the ultrafiltration (UF) and nanofiltration (NF) pretreatment effectively reduced the hardness and ionic content, enabling a stable PRO operation with real mining wastewater over a longer period of time. Overall, this study demonstrates the feasibility of achieving both reusable water and enhanced osmotic power generation using modified TFN membranes under realistic mining wastewater conditions. Full article

With the acceleration of industrialization, the problems of water resource pollution and shortage caused by oil spills and industrial wastewater discharge have become increasingly severe, posing a major threat to ecological sustainable development. Therefore, efficient oil–water separation technology has become a key breakthrough to alleviate this crisis. In this study, Janus membranes with asymmetric wettability were prepared by layer-by-layer electrospinning. The influence of the thickness ratio between the hydrophobic layer and the hydrophilic layer on the mechanical properties, separation flux, and oil–water mixture efficiency of the Janus membranes was examined, and an optimized membrane configuration was determined: the optimal thickness ratio between hydrophobic and hydrophilic layers was 4:6. Under these conditions, the fracture stress of the fiber membranes reached 99% MPa, the fracture strain was 55.63 ± 4.77%, the separation flux values were 1888.22 and 1042.66 L m⁻² h⁻¹ for the oil–water mixture and water-in-oil emulsion, respectively, with the separation efficiencies all exceeding 99%. After 50 cycles of separation for two different oil-in-water emulsions, the separation flux and separation efficiency of the optimal sample remained relatively stable, demonstrating strong practicability. In general, the Janus fiber membranes met the expected requirements, laying a good foundation for future applications in oil–water separation, floating oil collection in water, and other fields. Full article

Organic pollution poses a serious threat to global water safety, while traditional treatment technologies suffer from low efficiency, high costs, and secondary pollution issues. This study successfully develops a highly efficient separation and photocatalytic degradation composite bismuth oxychloride@graphene oxide/polyimide (BiOCl@GO/PI) membrane by loading GO and BiOCl photocatalysts onto PI supporting membrane. The results show that this composite membrane achieves a rejection of 99.8% for methylene blue (MB) and 87.6% for tetracycline hydrochloride (TC). Under UV irradiation, the membrane exhibits a retention rate decline of only 6.8% after five cycles, with water flux stably maintaining at 605 L m⁻² h⁻¹ bar⁻¹. Compared to dark conditions, it demonstrates remarkable flux recovery. This is attributed to the membrane’s excellent photocatalytic degradation activity under UV irradiation. After five degradation cycles, the degradation efficiency is decreased from 97.5 to 88.3%. Studies on radical scavengers indicate that UV irradiation generates free radicals, thereby conferring excellent catalytic activity to the membrane. Its unique synergistic effect between separation and photocatalysis endows it with outstanding self-cleaning performance. This research provides an innovative integrated solution for antibiotic pollution control, demonstrating significant potential for environmental applications. Full article

The adsorption of methylene blue (MB) on poly(vinylidene fluoride) (PVDF) and PVDF/titanium dioxide(TiO₂) membranes with 1.5 wt% dosage was examined through batch adsorption and dynamic cross-flow filtration experiments. The effects of pH, temperature, and initial MB concentration on adsorption performance were evaluated via batch experiments. The Thomas model was applied to analyze the membrane filtration process, while kinetic, isothermal, and thermodynamic models were integrated to elucidate the adsorption mechanisms. Results demonstrated that low temperature and high initial MB concentration significantly improved MB adsorption on both membranes. Under neutral pH conditions (pH = 7), the maximum adsorption capacities of PVDF and PVDF/TiO₂ membranes reached 1.518 ± 0.025 mg/g and 0.189 ± 0.008 mg/g, respectively. The adsorption processes on both membranes conformed to the pseudo-second-order kinetic model, with optimal fitting to the Langmuir isotherm model. Thermodynamic analysis revealed physical adsorption mechanisms, as evidenced by adsorption free energy (E) calculated via the Dubinin–Radushrevich model Notably, PVDF membrane exhibited a more pronounced mass transfer zone height (h_Z = 2.3 ± 0.1 cm) and achieved higher adsorption capacity (2.1 ± 0.09 mg/g) than PVDF/TiO₂ membranes (0.25 ± 0.01 mg/g). The TiO₂ incorporation reduced hybrid membrane adsorption capacity and significantly mitigated membrane fouling caused by adsorption, with PVDF/TiO₂ membranes showing a 32 ± 2.5% lower flux decline rate than PVDF membranes with less MB into the pores. This study provides fundamental data supporting the combined application of “adsorption–subsequent oxidation” using PVDF-based membranes in dye wastewater treatment. Full article

High regeneration energy demand remains a critical barrier to the large-scale deployment of ethanolamine-based (MEA-based) CO₂ capture. This study adopts an Al₂O₃ ceramic-membrane heat exchanger (CMHE) to recover both sensible and latent heat from the stripped gas. Experiments confirm that heat and mass transfer within the CMHE follow a coupled mechanism in which capillary condensation governs trans-membrane water transport, while heat conduction through the ceramic membrane dominates heat transfer, which accounts for more than 80%. Guided by this mechanism, systematic structural optimization was conducted. Alumina was identified as the optimal heat exchanger material due to its combined porosity, thermal conductivity, and corrosion resistance. Among the tested pore sizes, CMHE-4 produces the strongest capillary-condensation enhancement, yielding a heat recovery flux (q value) of up to 38.8 MJ/(m² h), which is 4.3% and 304% higher than those of the stainless steel heat exchanger and plastic heat exchanger, respectively. In addition, Length-dependent analyses reveal an inherent trade-off: shorter modules achieved higher q (e.g., 14–42% greater for 200-mm vs. 300-mm CMHE-4), whereas longer modules provide greater total recovered heat (Q). Scale-up experiments demonstrated pronounced non-linear performance amplification, with a 4 times area increase boosting q by only 1.26 times under constant pressure. The techno-economic assessment indicates a simple payback period of ~2.5 months and a significant reduction in net capture cost. Overall, this work establishes key design parameters, validates the governing transport mechanism, and provides a practical, economically grounded framework for implementing high-efficiency CMHEs in MEA-based CO₂ capture. Full article

Dysregulated magnesium (Mg²⁺) homeostasis contributes to colorectal cancer (CRC), yet its context-dependent function within the tumor microenvironment remains unresolved. This study aimed to determine how sustained low and high extracellular Mg²⁺ environments affect CRC spheroid (SP) growth and Mg²⁺ homeostasis using HT-29 SPs. We analyzed Mg²⁺ flux, the expression of Mg²⁺ transporters (e.g., Transient Receptor Potential Melastatin (TRPM) 6), viability, apoptotic and autophagic markers, and phospho-/oxidoproteomic alterations. Both Mg²⁺ extremes destabilized SP architecture, reduced viability, and induced apoptosis and autophagy, with SPs displaying heightened vulnerability relative to 2D cultures. Mg²⁺ stress impaired Mg²⁺ influx and eliminated adaptive transporter regulation in SPs. Loss of membrane TRPM6/7 heterodimers, driven by altered phosphorylation (e.g., TRPM6 Serine 141, Serine 1252, Threonine 1851) and elevated oxidation (e.g., Methionine 1755), suppressed channel activity. High Mg²⁺ caused profound metabolic failure despite increased total Mg²⁺, reflecting functional Mg²⁺ deficiency. CRC spheroids are acutely susceptible to Mg²⁺ imbalance due to collapsed transporter homeostasis and post-translational inhibition of Mg²⁺ channels. These findings reveal a targetable metabolic vulnerability and support the therapeutic potential of localized Mg²⁺ modulation in CRC. Full article

This study investigated the influence of two years of ultrafiltration (UF) on the separation properties of tubular polyvinylidene fluoride membranes used for treating carwash wastewater, particularly with regard to bacterial rejection. Fouling was mitigated by washing the membranes with alkaline cleaning agents (pH > 11.5). Repeated applications of these agents enlarged the membrane pores to approximately 300 nm. This affected bacterial retention, and for feed containing bacteria (determined as colony-forming units, CFU) at a concentration of 3.11 × 10⁶ CFU/mL, over 13,000 CFU/mL were detected in the permeate. Interestingly, fouling improved retention, reducing bacterial counts present in the permeate from 13,689 to 2889 CFU/mL. Fouling also enhanced the retention of surfactants (80%), chemical oxide domain (60%), and turbidity (below 0.5 NTU), yielding results comparable to new membranes. Daily 60-min membrane washing with Wheel Cleaner solution (pH = 11.5) improved the membranes performance; however, it did not remove deposits from large pores, allowing good rejection performance and a permeate flux of 65 LMH to be maintained. It was found that bacteria also developed on the permeate side. Disinfection of the module housing with a NaOH/NaOCl solution reduced the number of bacteria in the permeate from 5356 to 66 CFU/mL. Microbiological tests revealed that some of these bacteria were antibiotic-resistant. Full article