Search Results (147)

Overcoming the inherent permeability–selectivity trade−off is essential to broaden the practical application of polyamide (PA) reverse osmosis (RO) membranes in brackish water desalination. In this study, we developed a facile and cost-effective alkaline (NaOH) post-treatment method to fabricate high−performance loose-structured RO membranes. The NaOH post−treatment hydrolyzed part of the amide bonds within the membrane, converting them to negatively charged carboxyl groups. This process led to a slight increase in pore size and the formation of a looser structure. Molecular weight cut−off (MWCO) measurements confirmed that the pore size slightly increased from 0.19 nm to 0.21 nm, while X−ray photoelectron spectroscopy (XPS) and zeta potential measurements confirmed the conversion of amide bonds to carboxyl groups, which further enhanced the surface electronegativity. The synergistic effects of pore size enlargement and surface charge modification were elucidated as the key mechanisms for performance enhancement. The TPA membrane exhibited a 2−fold increase in water permeance (from 1.05 to 3.21 L m⁻² h⁻¹ bar⁻¹), while the enhanced surface negative charge contributed to maintaining a high NaCl rejection of 98.5%. Additionally, the membrane also exhibited excellent pH stability as well as long-term stability over 100 h of continuous operation. This easily scalable post−treatment strategy offers a low−cost route to fabricate loose-structured membranes, with significant potential to enhance efficiency and reduce costs in brackish water desalination. Full article

The purpose of this study was to assess the suitability of tubular polymeric ultrafiltration membranes for use in a closed-loop water system within a rubber manufacturing plant. This research focused on determining the transport and separation properties of polymeric tubular membranes during the ultrafiltration of wastewater generated from washing vulcanised rubber hoses. The tests were conducted using the installation of the UF-1 membrane supplied by APEKO Sp. z o.o. This study evaluated the performance of modified PES membranes with a molecular weight cut-off (MWCO) of 4 kDa and PVDF membranes with MWCO of 100 kDa in the wastewater treatment process, as well as the effectiveness of membrane regeneration. Given the characteristics of wastewater, the key parameters for evaluating ultrafiltration performance included the determination of contaminant separation coefficients (R, %) for non-ionic surfactants (NIS) and chemical oxygen demand (COD), as well as turbidity reduction. The results demonstrated that the tested membranes substantially improved the visual quality of the wastewater by reducing turbidity by more than 95% and exhibited high separation efficiency for the analysed contaminants, with initial values of R_NIS = 95% and R_COD = 85% at the beginning of the ultrafiltration cycle, decreasing to R_NIS < 10% and R_COD < 10% after several hours of operation. During closed-loop filtration, when a twentyfold concentration of contaminants in the retentate was reached, membrane fouling occurred, significantly reducing filtration performance. Chemical cleaning enabled the recovery of approximately 70% of the initial performance for modified PES membranes and 60% for PVDF membranes. Full article

Background/Objectives: Assessing the bioavailability of nutrients and bioactive compounds in vitro commonly relies on coupling standardized gastrointestinal digestion models with intestinal epithelial cell systems. However, digests produced using static digestion protocols such as INFOGEST often impair epithelial barrier integrity, limiting their direct application to intestinal models and reducing reproducibility across studies. Methods: This work systematically compared five commonly used digest conditioning strategies, including acidification, centrifugation, rapid freezing, and ultrafiltration using 10 kDa and 3 kDa molecular weight cut-off membranes, to identify the approach that best preserves intestinal epithelial viability and barrier function while enabling exposure at physiologically relevant concentrations. INFOGEST digests of yogurt were initially evaluated, followed by validation using biscuit and canned mackerel digests. Cell viability and monolayer integrity were assessed in differentiated Caco-2 cells using MTT assay and transepithelial electrical resistance (TEER) measurements. Results: Among the tested approaches, ultrafiltration using 3 kDa membranes consistently preserved epithelial viability and barrier integrity at a 1:10 dilution across all food matrices, whereas other conditioning methods failed to maintain TEER despite acceptable cell viability. At lower dilutions, food-dependent effects emerged, highlighting the importance of matrix-specific evaluation. Conclusions: These findings identify 3 kDa ultrafiltration as an effective and minimally invasive strategy to improve the compatibility of INFOGEST digests with intestinal cell models. By enabling reproducible exposure conditions that preserve epithelial integrity, this approach supports more reliable in vitro assessment of nutrient bioavailability and contributes to methodological standardization in nutrition research. Full article

In whey valorization, membrane separation stands out as a highly effective technique for purifying and isolating the various components of whey. The efficiency of whey ultrafiltration and diafiltration (UF/DF) largely depends on the balance between membrane selectivity, hydrodynamic conditions, and solute interactions at the membrane interface. In this study, sweet whey was fractioned using 10, 30 and 50 kDa polyether sulfone (PES) membranes under identical transmembrane pressure (TMP = 2.5 bar) with ultrafiltration and a subsequent 4-step constant volume diafiltration stages. The resulting compositional and dielectric changes were evaluated to identify optimal separation conditions and assess the applicability of dielectric parameter measurement as a rapid, non-destructive monitoring technique. Results showed that, regardless of the applied molecular weight cut-off (MWCO), using three DF cycles can wash out almost all the removable lactose from the retentates, and the dielectric assessment of both permeate and retentate fractions showed a strong, linear relationship between the change in dielectric behavior and the composition of each fraction. Analysis of the dielectric spectra confirmed that the ratio of the dielectric constant to the loss factor (ε′/ε″) exhibited a strong linear correlation (R² > 0.98, r > 0.99) with lactose concentration in the permeate fractions of all three MWCO membranes, as well as a similarly strong correlation (R² > 0.975, r > 0.98) with the total chemical oxygen demand (TCOD) measured in the retentate fractions. Full article

Tobacco extract contains numerous valuable components, among which nicotine possesses significant potential for high-value applications despite its well-known health risks. However, the efficient extraction of nicotine is challenging due to the complex composition of tobacco extracts and the limitations of conventional separation techniques. In this work, an integrally asymmetric nanofiltration membrane was developed via thermal cross-linking for highly efficient nicotine separation. A poly(aryl ether ketone) (PEK)-based ultrafiltration membrane was first prepared via non-solvent induced phase separation (NIPS), followed by controlled thermal cross-linking to tailor the membrane pore size toward the molecular weight of nicotine. To mitigate pore collapse and enhance flux, TiO₂ nanoparticles were incorporated in situ through a sol–gel method. The resulting thermally cross-linked membrane exhibited a molecular weight cut-off of ~180 Da, a nicotine rejection rate of 93.2%, and a permeation flux of 143 L/(m²·h)—representing a 259% increase over the control membrane. Moreover, the thermally cross-linked membranes demonstrated exceptional chemical stability in various organic solvents and extreme pH conditions. This work offers a feasible and sustainable strategy for fabric high-performance nanofiltration membranes for the targeted extraction of bioactive molecules from complex plant extracts. Full article

This study aimed to identify a probiotic bacterium with antagonistic activity against the foodborne pathogen Staphylococcus aureus (S. aureus) and investigate the mechanism of its antibacterial components. Growth kinetics were analyzed to assess bacterial proliferation. Acid and bile salt tolerance are vital indicators for evaluating probiotic survival in the gastrointestinal tract. The results indicated that Companilactobacillus farciminis (C. farciminis) YLR-1 not only had high tolerance to salt conditions (0.03%, 0.3%, and 0.5%) but also has a high survival rate at pH 3–4. The bacteriocin-like inhibitory substance (BLIS) isolated from C. farciminis YLR-1 was dialyzed using a membrane with a molecular weight cut-off (MWCO) of 500 Da, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The results indicate that the BLIS produced by C. farciminis YLR-1 is a small-molecule peptide. BLIS displayed pH tolerance within acidic and neutral environments (4–8) and exhibited thermostability. When treated with proteinase K, the antibacterial action of BLIS was found to be inactivated. Membrane disruption mechanisms were examined using fluorescence imaging and scanning electron microscopy (SEM). SEM and fluorescence imaging revealed that BLIS-induced membrane damage in S. aureus ATCC 25923 causes cytoplasmic leakage and cell death. Full article

In vitro cartilage explant culture has been used to assess nutraceuticals on cartilage responses to inflammatory stimuli. However, applying extracts of nutraceuticals directly to cartilage explants does not account for effects of digestion and hepatic biotransformation, or selective exclusion of product metabolites from joint fluid by the synovial membrane. The current study produced a simulated biological extract of a common nutraceutical (glucosamine; G_sim) by exposing it to a simulated upper gastrointestinal tract digestion, hepatic biotransformation by liver microsomes, and purification to a molecular weight cut-off of 50 kDa. This extract was then used to condition cartilage explants cultured for 120 h in the presence or absence of an inflammatory stimulus (lipopolysaccharide). Media samples were analyzed for prostaglandin E₂ (PGE₂), glycosaminoglycan (GAG), and nitric oxide (NO). Tissue was digested and analyzed for GAG content and stained for viability. Conditioning of explants with G_sim significantly reduced media GAG in stimulated and unstimulated explants and reduced nitric oxide production in unstimulated explants. These data provide evidence for the value of glucosamine in protecting cartilage from deterioration following an inflammatory challenge, and the model improves applicability of these in vitro data to the in vivo setting. Full article

Nanofiltration (NF) is considered a competitive purification method for acidic stream treatments. However, conventional thin-film composite NF membranes degrade under acid exposures, limiting their applications in industrial acid treatment. For example, wet-process phosphoric acid contains impurities of multivalent metal ions, but NF membrane technologies for impurity removal under harsh conditions are still immature. In this work, we develop a novel strategy of acid-resistant nanofiltration membranes based on interfacial polymerization (IP) of polyethyleneimine (PEI) and cyanuric chloride (CC) with the s-triazine ring. The IP process was optimized by orthogonal experiments to obtain positively charged PEI-CC membranes with a molecular weight cut-off (MWCO) of 337 Da. We further applied it to the approximate industrial phosphoric acid purification condition. In the tests using a mixed solution containing 20 wt% P₂O₅, 2 g/L Fe³⁺, 2 g/L Al³⁺, and 2 g/L Mg²⁺ at 0.7 MPa and 25 °C, the NF membrane achieved 56% rejection of Fe, Al, and Mg and over 97% permeation of phosphorus. In addition, the PEI-CC membrane exhibited excellent acid resistance in the 48 h dynamic acid permeation experiment. The simple fabrication procedure of PEI-CC membrane has excellent acid resistance and great potential for industrial applications. Full article

Traditional pre-clinical drug evaluation methods, including animal experiments and static cell cultures using human-derived cells, face critical limitations such as interspecies differences, ethical concerns, and poor physiological relevance. More recently, microphysiological systems (MPSs) that use microfluidic devices to mimic in vivo conditions have emerged as promising platforms. By enabling perfusion cell culture and incorporating human-derived cells, MPSs can evaluate drug efficacy and toxicity in a more human-relevant manner. However, standard MPS protocols rely on discrete medium changes, causing abrupt changes in drug concentrations that do not reflect the continuous pharmacokinetics seen in vivo. To overcome this limitation, we developed a Dialysis Membrane-integrated Microfluidic Device (DMiMD) which maintains continuous drug concentrations through selective medium change via a dialysis membrane. The membrane’s molecular weight cut-off (MWCO) enables the retention of high-molecular-weight drugs while facilitating the passage of essential low-molecular-weight nutrients such as glucose. We validated the membrane’s molecular selectivity and confirmed effective nutrient supply using cells. Additionally, anticancer drug efficacy was evaluated under continuously changing drug concentrations, demonstrating that the DMiMD successfully mimics in vivo drug exposure dynamics. These results indicate that the DMiMD offers a robust in vitro platform for accurate assessment of drug efficacy and toxicity, bridging the gap between conventional static assays and the physiological complexities of the human body. Full article

This study aimed to produce antioxidant peptide fractions from Skipjack tuna (Katsuwonus pelamis) head by-products through enzymatic hydrolysis and membrane filtration. Raw materials were sequentially hydrolyzed with Alcalase^® (4 h) and Flavourzyme^® (1 h), reaching a final degree of hydrolysis of 18.5 ± 0.9%. The crude hydrolysate was fractionated using ceramic membranes with molecular weight cut-offs of 8, 3, and 1 kDa. Some peptide fractions presented a relevant proportion of short-chain peptides (>50% w/w) and free amino acids (>10% w/w), as well as a high content of essential amino acids (>64% mol), supporting their value as dietary ingredients for aquafeeds. In vitro antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferrous ion chelation assays. Some fractions (e.g., F3R1 with IC₅₀ = 1.04 ± 0.01 mg·mL⁻¹ for metal chelating activity) displayed significantly improved (p < 0.05) antioxidant properties compared to the unfractionated hydrolysate (IC₅₀ = 2.75 ± 0.08 mg·mL⁻¹). This may be linked to their molecular weight profile and hydrophobic amino acid content. These results demonstrate the potential of the proposed approach to obtain bioactive peptide fractions with functional properties for aquafeeds. Zootechnical trials are needed to assess their effects on feed utilization and in vivo mitigation of oxidative stress. Full article

This study examined total ammoniacal nitrogen (TAN) rejection by two reverse osmosis (RO) and two nanofiltration (NF) membranes as a function of pH for three ammonium salts to optimize conditions for a hybrid membrane system that can produce high-purity TAN streams suitable for reuse. The results showed that TAN rejection was significantly influenced by membrane type, feed pH, and the ammonium salt used. This study represents the first attempt to simulate real manure wastewater conditions typically found in pig manure. TAN rejection for (NH₄)₂SO₄ and NH₄HCO₃ reached up to 95% at pH values below 7, with the SW30 membrane showing the highest performance (99.5%), attributed to effective size exclusion and electrostatic repulsion of SO₄²⁻ and HCO₃⁻ ions. In contrast, lower rejection was observed for NH₄Cl, particularly with the MPF-34 membrane, due to its higher molecular weight cut-off (MWCO), which diminishes both exclusion mechanisms. TAN rejection decreased markedly with increasing pH across the BW30, NF90, and MPF-34 membranes as the proportion of uncharged NH₃ increased. The lowest rejection rates (<15%) were recorded at pH 11.5 for both NF membranes. These results reveal a notable shift in separation behavior, where NH₃ permeation under alkaline conditions becomes dominant over the commonly reported NH₄⁺ retention at low pH. This novel insight offers a new perspective for optimizing membrane-based ammonia recovery in systems simulating realistic manure wastewater conditions. TAN recovery was evaluated using a hybrid membrane system, where NF membranes operated at high pH promoted NH₃ permeation, and the SW30 membrane at pH 6.5 enabled TAN rejection as (NH₄)₂SO₄. This hybrid system insight offers a new perspective for optimizing membrane-based ammonia recovery in systems simulating realistic manure wastewater conditions. Based on NH₃ permeation and membrane characteristics, the NF90 membrane was operated at pH 9.5, achieving a TAN recovery of 48.3%, with a TAN concentration of 11.7 g/L, corresponding to 0.9% nitrogen. In contrast, the MPF-34 membrane was operated at pH 11.5. The NF90–SW30 system also achieved a TAN recovery of 48.3%, yielding 11.7 g/L of TAN with a nitrogen content of 1.22%. These nitrogen concentrations indicate that both retentate streams are suitable for use as liquid fertilizers in the form of (NH₄)₂SO₄. A preliminary economic assessment estimated the chemical consumption cost at 0.586 EUR/kg and 0.729 EUR/kg of (NH₄)₂SO₄ produced for the NF90–SW30 and MPF-34–SW30 systems, respectively. Full article

Chronic kidney disease (CKD) is a global health burden, with uremic toxins (UTs) playing a central role in its pathophysiology. In this review, we systematically examined the evolution of UT classification from the 2003 European Uremic Toxin Work Group (EUTox) system based on molecular weight and protein-binding properties to the 2023 multidimensional framework integrating clinical outcomes, clearance technologies, and artificial intelligence. We highlighted the toxicity mechanisms of UTs across the cardiovascular, immune, and nervous systems and evaluated traditional (e.g., low-/high-flux hemodialysis) and advanced (e.g., high-cutoff dialysis and hemoadsorption) clearance strategies. Despite progress, challenges persist in toxin detection, clearance efficiency, and personalized therapy. Future directions include multi-omics-based biomarker discovery, optimized dialysis membranes, advanced adsorption technology, and AI-driven treatment personalization. This synthesis aims to bridge translational gaps and guide precision medicine in nephrology. Full article

This study investigated the use of ultrafiltration for sustainable protein recovery and the treatment of shrimp washing wastewater (SWW). Three ultrafiltration membranes with molecular weight cut-offs of 5, 10, and 50 kDa were tested using a combined ultrafiltration–diafiltration process (UF-DF). The performance of each membrane was assessed based on protein recovery efficiency, chemical oxygen demand (COD) reduction, turbidity, fouling behavior, and cleaning efficiency. The 5 kDa membrane showed superior performance, achieving over 90% protein and COD rejection and producing the highest protein-enriched retentate. It also exhibited the lowest fouling index and best cleaning recovery, confirming its suitability for protein concentration and wastewater treatment. This research highlights UF-DF as a promising, eco-efficient technology for valorizing seafood processing effluents by recovering high-value proteins and reducing environmental discharge loads. Full article

The recovery of lithium from extracts obtained from a black mass of spent lithium-ion batteries treated with a ternary solvent system at acidic pH was investigated using flat-sheet nanofiltration (NF) membranes operated according to a dead-end configuration. Specifically, four samples obtained at different pH values (2.5 and 5) and extraction times (48, 96 and 168 h) were treated in selected operating conditions by using two commercial polymeric membranes (denoted DK and HL, with an approximate molecular weight cut-off of 150–300 Da) up to a volume reduction factor (VRF) of 4. Membrane performance was assessed in terms of productivity and selectivity towards specific ions, including lithium. For most treated samples, the HL membrane exhibited higher permeate fluxes in comparison to the DK membrane. However, the DK membrane performed better in terms of lithium rejection than the HL membrane, with a negative rejection at VRF 4 observed for all treated samples. More than 90% of multivalent ions were rejected by both membranes independently of the VRF. The membrane ability to retain multivalent ions led to their progressive concentration in the retentate as the VRF increased. The extraction time did not impact the NF performance of both membranes in terms of ion rejection. For the DK membrane conditions of extraction of 96 h and pH 5 represented the best trade-off between flux, ion rejection, and total lithium recovery. Full article

Hypertension and type 2 diabetes are the major metabolic syndromes, often managed using synthetic ACE and DPP-IV inhibitors that may cause adverse effects on health. This study investigated Bambara groundnut protein hydrolysates as a natural source of dual ACE- and DPP-IV-inhibitory peptides. Protein isolates were hydrolyzed using Flavourzyme, and the resulting peptides were fractionated using membranes with different molecular weight cut-offs. Those fractions were then analyzed for enzyme inhibition. Peptides were identified by LC-MS/MS and screened using PeptideRanker and BIOPEP-UWM, followed by molecular docking against ACE (PDB: 1O8A) and DPP-IV (PDB: 1NU6). The >10 kDa and 5–10 kDa fractions showed the highest ACE- and DPP-IV-inhibitory activities, respectively. Some peptides such as YKDGLYSPHW, LPVSTPGKF, and EPWWPK displayed strong binding affinities (ΔG: −10.2 to −11.3 kcal/mol for ACE, −8.6 to −9.1 kcal/mol for DPP-IV) and interacted with key catalytic residues, including His387 and Glu411 in ACE, and Ser630, Glu205, and Phe357 in DPP-IV. These findings highlight the potential of Bambara groundnut hydrolysates or peptides as a source of natural ACE and DPP-IV inhibitors. Full article