Membrane Surface Research Articles

Investigating mechanism of enhanced anti-fouling performance of MXene modified Janus MD membrane by XDLVO theory combined with surface elemental integration method

Organic membrane fouling is a major obstacle to the application of membrane distillation in low surface tension wastewater treatment. Membrane modification might be an effective way to mitigate membrane fouling. This study mainly explored the mechanism of enhanced anti-fouling performance of the MXene modified PVDF membrane by applying XDLVO theory combined with surface elemental integration (SEI) method. The rough membrane surfaces were first reconstructed using fractal function. Then, the interaction energy between low surface tension substances and the membranes before and after modification was calculated. The results showed that oil droplets and surfactant fouling were mainly caused by hydrophobic attraction due to Lewis acid-base (AB) interaction energy. By modifying the virgin PVDF membrane with MXene nanoparticles, the polar component of membrane surface tension (γAB) increased significantly, so that the interaction energy between all contaminants and membrane surface changed from attraction to repulsion. In addition, roughness weakened the interaction energy between contaminants and membrane surface but significantly lengthened the range of interaction distance, which together determined the ability of the membrane to attract or repel the contaminants. These findings may improve the understanding of the structure-effect relationship between membrane modification and anti-fouling ability, and provide new insights into the membrane modification for MD.

Insights of membrane fouling under scale inhibitor synergistic condition monitored by ultrasonic phased array: Fouling spatial and density characteristics

Achieving accurate dosing of scale inhibitors in full reverse osmosis (RO) membrane systems for industrial applications is a critical challenge due to a lack of understanding of membrane fouling characteristics. To address this, this study investigated membrane performance at different inhibitor concentrations and proposed a method using ultrasonic phased arrays (UPA) to evaluate the fouling layer's spatial and density characteristics. The study also examined the relationship between fouling reversibility and compaction, and the results showed a clear conversion process from inhibition to exacerbation of membrane fouling by scale inhibitors. Additionally, the fouling layer distribution characteristics were opposite at different concentrations. At insufficient concentrations, the scaling layer forms near the outlet and spreads to the far-end with a continuously decreasing thickness. Conversely, at surplus concentrations, the opposite effect was observed. At sufficient concentrations, the fouling layer thickness and range exhibited a discontinuous distribution. The high-density layer was dominant on the membrane surface and showed low fouling reversibility. However, scale inhibitors were found to minimize fouling density by interfering with ion deposition, reducing the ion content and significantly increasing its reversibility. These findings have significant implications for scale inhibitor efficiency evaluation and scientific application, which can improve industrial membrane system performance.

Synergy of Cu-Mn bimetals under nano-confined catalysis in a membrane-based peroxymonosulfate system

The electronic interactions of bimetals were investigated in the confined membrane environment. In this work, Cu-Mn oxides were loaded on polytetrafluoroethylene (PTFE) membrane surface for nano-confined PMS activation and sulfamethoxazole (SMX) degradation. The CuO@MnO2/PTFE membrane achieved SMX removal with constant of 0.1268 min−1 in PMS system, which was higher than that in traditional advanced oxidation process (0.0949 min−1). The confined Cu and Mn sites enhanced electronic coupling, which promoted the electron rearrangement of metal sites and facilitated PMS adsorption and activation. As a result, SO4•− (48.11%) and •OH (31.78%) played a dominant role in CuO@MnO2/PTFE membrane/PMS system, hence achieving faster removal of SMX. The obtained results help to understand the PMS activation process with confined bimetals, which ultimately promotes the development and application of confined catalysis.

Scaling behavior in membrane distillation: Effect of Biopolymers and Antiscalants

Fouling and scaling are inherent characteristics of membrane-based separation. They lead to a reduced membrane throughput. In the case of membrane distillation (MD), they can possibly result in pore wetting and irreversible failure to sustain the mass transfer interface. Most prior research on understanding fouling and scaling uses indirect measurements (flux) or ex-situ analyses methods (such as SEM and EDX), which limit the outcomes to indirect qualitative conclusions. Particularly, studying scaling tends to be more challenging due to the complexity of the experiments and the method of investigation; it is imperative to distinguish the contributions from the bulk phase and heterogeneous nucleation. In this work, we established a non-invasive, in-situ, real-time imaging experimental apparatus to study the scaling mechanism. Our experimental setup assisted us in distinguishing distinct phases of scaling during the filtration tests. We studied the scaling mechanism of various single-component systems (sodium chloride, strontium sulfate, calcium sulfate, and calcium carbonate) in vacuum MD filtration. The effect of natural organic matter and antiscalants on gypsum scaling were systematically investigated. Overall, organic fouling on the membrane surface expedited heterogeneous crystallization while decelerating crystal growth in the bulk phase. For instance, deposited humic acid (HA) on the membrane surface promoted gypsum heterogeneous nucleation on the membrane surface due to the interactions between HA carboxylic functional groups and calcium ions. The adsorption of HA on the salt crystal also decelerated crystal growth in the bulk phase. Antiscalants delayed and decelerated both crystal nucleation and crystal growth. PAA, a polycarboxylate antiscalant at 5 ppm, was found to effectively delay the onset of nucleation and crystal growth in the bulk phase, while phosphorous antiscalants at 5 ppm only delayed the onset of nucleation in the bulk phase with a negligible influence on crystal growth. Real-time, in-situ, and non-invasive monitoring shed light on the scaling mechanism and can further be used to identify mitigation strategies.

Design of hydrophobic polymer brush for mitigation of membrane wetting in membrane distillation- computer simulation

Defined as an assembly of polymer chains which are tethered by one end to a surface or an interface, polymer brushes have found many applications. In particular, grafting of hydrophilic polymer brushes to the membrane surface was used to mitigate fouling of filtration membranes. As well, hydrophobic polymer brushes were grafted on top of a solid substrate to be used for organic selective pervaporation. In this work, grafting of hydrophobic brushes to the surface of membranes for membrane distillation (MD) is proposed to prevent MD membranes from wetting. This is not an experimental work but a computer simulation of designing the polymer brush or patterned polymer brush to optimize their effect on wetting prevention. It was found that such an effect increases with an increase in the distance between brushes, the contact angle and the radius of the cylindrical polymer brush. Considering the decrease in the effective area of the membrane used for vapor permeation by grafting of polymer brush, the optimal distance between the brushes was found to be twice as large as the brush diameter for millimeter-sized brush and three times as large as the brush diameter of micro- or nanometer sized brushes.

Solubilization of Phospholipid by Surfactin Leading to Lipid Nanodisc and Fibrous Architecture Formation.

Nanodiscs belong to a category of water-soluble lipid bilayer nanoparticles. In vivo nanodisc platforms are useful for studying isolated membrane proteins in their native lipid environment. Thus, the development of a practical method for nanodisc reconstruction has garnered consider-able research interest. This paper reports the self-assembly of a mixture of bio-derived cyclic peptide, surfactin (SF), and l-α-dimyristoylphosphatidylcholine (DMPC). We found that SF induced the solubilization of DMPC multilamellar vesicles to form their nanodiscs, which was confirmed by size-exclusion chromatography, dynamic light scattering, and transmission electron microscopy analyses. Owing to its amphiphilic nature, the self-assembled structure prevents the exposure of the hydrophobic lipid core to aqueous media, thus embedding ubiquinol (CoQ10) as a hydrophobic model compound within the inner region of the nanodiscs. These results highlight the feasibility of preparing nanodiscs without the need for laborious procedures, thereby showcasing their potential to serve as promising carriers for membrane proteins and various organic compounds. Additionally, the regulated self-assembly of the DMPC/SF mixture led to the formation of fibrous architectures. These results show the potential of this mixture to function as a nanoscale membrane surface for investigating molecular recognition events.

Thermally induced phase separation PVDF membrane fabricated by using NaCl coagulation bath: Relation of membrane surface morphology and permeation performance

Efforts have been made in thermally induced phase separation (TIPS) process to modify the morphology of polyvinylidene fluoride (PVDF) membranes in order to improve their permeation performance and mechanical properties. Nevertheless, many methods not only altered the outer surface but also impacted the overall membrane structure, resulting in a trade-off between permeability and mechanical properties. In this study, we utilized a modified TIPS process to refine the outer surface morphology without altering the bulk structure. This was achieved by introducing NaCl in the coagulation bath. The PVDF membranes were fabricated using a dope with water insoluble diluent dimethyl phthalate (DMP) as main solvent and water-soluble additives polyethylene glycol 400 (PEG400)/triethylene glycol (TEG) as pore formers. The inclusion of NaCl in the coagulation bath serves to decrease the solubility of PEG within this medium, owing to the salting-out effect. Consequently, the NaCl concentration in the coagulation bath emerges as a crucial factor in regulating the migration of PEG400 toward the membrane surface. This control mechanism facilitates the precise adjustment of the outer surface morphology in the fabrication of membranes. As the NaCl concentration increases in the coagulation bath, the outer surface of the fabricated membrane transited from a mesh-like structure to a spherulite structure. As 0.5 mol L−1 NaCl was added to the coagulation bath, the membranes displayed a pure water permeability of 1073.9 L m−2 h−1 bar−1 while maintaining a narrow pore size distribution. Compared to the membranes fabricated without NaCl addition, the increment of the PWP contributed to the slight increase in mean pore size from 65 nm to 84 nm. Meanwhile, the water-insoluble diluent DMP was not affected by the addition of NaCl, which means that the bulk structure of the membrane could be maintained. Consequently, the increase in permeability did not compromise the mechanical properties of the membranes. All the membranes fabricated in this study maintained a reasonable tensile strength of approximately 3 MPa. This study introduces a simple and environmental method to increase the permeability effectively and fine-tune the pore size of the TIPS membranes while having little effect on the bulk structure. Furthermore, the study provides valuable insights into how changes in outer surface morphology can impact the pore size and permeability of TIPS PVDF membranes.

Photocatalytic Zinc Oxide Nanoparticles in Antibacterial Ultrafiltration Membranes for Biofouling Control.

Global water scarcity is a threat that can be alleviated through membrane filtration technologies. However, the widespread adoption of membranes faces significant challenges, primarily due to membrane biofouling. This is the reason why membrane modifications have been under increasing investigation to address the fouling issues. Antibacterial membranes, designed to combat biofouling by eliminating microorganisms, offer a promising solution. Within this study, flat sheet ultrafiltration (UF) membranes with integrated photocatalytic zinc oxide (ZnO) nanoparticles were developed, characterized, and assessed through filtration and fouling tests. The antibacterial properties of the membranes were conducted in static tests using Gram-negative bacteria-Escherichia coli-and natural tap water biofilm. The results demonstrated a notable enhancement in membrane surface wettability and fouling resistance. Furthermore, the incorporation of ZnO resulted in substantial photocatalytic antibacterial activity, inactivating over 99.9% of cultivable E. coli. The antibacterial activity persisted even in the absence of light. At the same time, the persistence of natural tap water organisms in biofilms of modified membranes necessitates further in-depth research on complex biofilm interactions with such membranes.

Carbon black-coated SPEEK membrane for efficient vanadium flow batteries

Ion exchange membrane is a key component of vanadium flow batteries (VFB). Development of low-cost and high ion selectivity membrane is essential to promote practical application of VFB. Here we report a kind of carbon-coated membrane by spraying coating Super P/polyvinylidene fluoride slurries on the surface of sulfonated poly(ether ether ketone) membrane (SPEEK/SP@PVDF). The SP attached to the membrane surface or infiltrated into the membrane matrix can synergistically promote the transport of protons while inhibiting the penetration of vanadium ions. In addition, the surface SP@PVDF layer can effectively shield the strong oxidizing VO2+ in the posolyte. As a result, the VFB with the optimized SPEEK/SP@PVDF membrane demonstrates a stable energy efficiency of >80 % at 200 mA cm−2 and a peak power density of 1073.79 mW cm−2 at 1300 mA cm−2, indicating the great potential of this carbon black-coated membrane for potential application in VFB.

Controlled architecture of multi-defense anti-fouling forward osmosis membrane for efficient shale gas wastewater treatment

Forward osmosis (FO) membrane process facilitates effective treatment of shale gas wastewater (SGW) due to its tolerance to high salinity and exceptional separation performance. However, serious membrane fouling remains a challenge regarding the complexity of realistic SGW. To address the fouling issues, controlled block copolymer architecture was constructed on the FO membrane surface to achieve combined effect of oil-resistance, self-regenerating, and fouling mitigation. In the modification process, zwitterionic polymer with strong hydrophilicity and fluoropolymers with low surface energy were successively grafted to the membrane active layer by atom transfer radical polymerization. The outermost fluoropolymer layer with low surface energy imparts the membrane with anti-oil and self-regenerating capabilities. Meanwhile, the strong hydration effect of the zwitterionic polymer ensures that nonspecific foulants breaking through the outermost defense are kept away from the membrane surface. According to the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the modified FO membrane exhibited a significantly higher total interaction energy (ΔGTOT) compared to the pristine membrane when exposed to various types of model foulants (bovine serum albumin, humic acid, sodium alginate, mineral oil). Furthermore, the advantage of having multiple defense mechanisms was further substantiated through dynamic filtration tests with realistic SGW. In comparison to the pristine TFC membrane, the modified membrane not only experienced a much smaller decrease in water flux (reduced by 52%) during fouling but also an exceptional flux recovery after cleaning (∼97%). These findings underscore that the modified FO membranes greatly mitigated membrane fouling associated with SGW through the synergistic interplay between a zwitterionic polymer and a low surface energy material, highlighting its promising potential in SGW treatment via membrane technology.

Deciphering the behavior and potential mechanism of biochar at different pyrolysis temperatures to alleviate membrane biofouling

Biofouling limits applications of membrane technology in wastewater treatment, but dosing additives to membrane tanks is an effective method to alleviate biofouling. In this study, biochar derived from corncob and pyrolyzed at 300, 500, and 700°C was dosed to determine the underlying anti-biofouling mechanism. The effects of the biochar on the membrane properties and foulant behavior were systematically investigated. The results showed that biochar delayed the occurrence of the fouling transition (0.5–3.0 h), and decreased the flux decline rate, thus achieving a higher water flux (3.1–3.7 times of the control group). Biochar altered membrane surface properties, and increased the membrane surface charge, roughness, and hydrophilicity, which all contributed to higher membrane permeability. Moreover, adding biochar reduced the number of foulants in the fouling layer, particularly protein substances. The flux model fit and the XDLVO theory further revealed the mitigating effect of biochar on membrane biofouling. At the initial intermediate-blocking stage, the effect of biochar on membrane fouling was determined by its properties, and adsorption capacity to the foulants, BC500 presented the best mitigation performance. At the later cake-filtration stage, the role of biochar in membrane fouling was strongly associated with protein content in the fouling layer, and the minimum rate of flux decline occurred in BC300. This study promotes the understanding and development of biochar to alleviate membrane biofouling.

Dextran sulfate bulk and surface-modified microfiltration membrane for simultaneous blood plasma harvesting and low-density lipoprotein removal during plasmapheresis

Plasmapheresis is currently used for the harvesting of blood plasma in medical labs and plasma donation centers. This is a fast, single-step membrane process for both collection of blood plasma and simultaneous blood cell isolation. This paper presents the development of a novel membrane that can be used to simultaneously harvest blood plasma and isolate low-density lipoprotein (LDL), known as bad cholesterol, from the blood. To achieve this goal, dual surface and bulk modification by dextran sulfate (DS) was performed on a polyethersulfone (PES) membrane containing single wall carbon nanotubes (SWCNT). DS is an anionic ligand that repels negatively charged substances like red blood cells (RBCs) and adsorbs positively charged substances like Apo B100; the apoprotein of LDL. Scanning Electron Microscope (SEM), Energy Dispersive X-Ray (EDX), and Fourier Transform Infrared (FTIR) spectroscopy analyses provided evidence of the grafting of DS on single wall carbon nanotubes (DS-SWCNT). Surface studies including water contact angle, zeta potential analysis, surface morphology, Attenuated Total Reflectance-FTIR (ATR-FTIR), and EDX, confirmed the presence of DS on the PES membrane surface. The SEM cross-section results showed the formation of a two-zone morphology with an open structure on the upside and a dense structure on the downside that provide optimal conditions for efficient separation of blood cells. The complete blood count (CBC) and biochemistry analyses revealed dual bulk and surface-modified membrane, and a specific sample (DM2) showed the best performance for blood cells and LDL separation. The maximum separation of blood cells was 87% RBC, 98% white blood cells (WBCs), and 83% platelets (PLTs). Moreover, DM2 exhibited a sieving ratio for LDL of 0.33. Blood compatibility analyses confirmed that DM2 and other related samples had low hemolysis and prolonged coagulation times.

Zeta potential characterization of the effects of fouling and cleaning of hollow fibre forwards osmosis membrane modules

Commercial Aquaporin Inside® hollow fibre forward osmosis (HFFO) membranes embedded in lab-scale filtration modules were employed to study their fouling propensity during forward osmosis (FO) up-concentration of a fermentation broth resulting from vaccine production. The fouling and subsequent cleaning processes were analysed in terms of the lumen side active layer zeta potential of the HFFO membranes. The zeta potential indicated significant adsorption of contaminants from the feed solution on the membrane's active surface. Various cleaning conditions: alkaline, alkaline + surfactant, complexation and acidic (hydrochloric and citric), were used to investigate the potential enhancement of contaminant removal compared to a simple rinse with deionized water. Despite a full recovery of the membrane performance after cleaning, the zeta potential measurements indicated contaminants remaining on the membrane surface. The extent of this residual contamination depends strongly on the applied cleaning conditions. Rinsing with deionized water and alkaline cleaning (with or without surfactant) results in a shift in the fouled membrane isoelectric point (IEP) with a concomitant shift of the zeta potential towards the IEP and zeta potential of the pristine membrane. However, cleaning with either the complexation agent or under acidic conditions exhibits a more negative zeta potential of the fouled HFFO membranes compared to the pristine membrane, indicating an additional effect superimposed on the removal of organic contaminants.

Human erythrocytes under stress. Spectroscopic fingerprints of known oxidative mechanisms and beyond

In this work, we investigated the oxidative stress-related biochemical alterations in red blood cells (RBCs) and their membranes with the use of spectroscopic techniques. We aimed to show their great advantage for the in situ detection of lipid classes and secondary structures of proteins without the need for their extraction in the cellular environment. The exposition of the cells to peroxides, t-butyl hydroperoxide (tBOOH) or hydrogen peroxide (H2O2) led to different degradation processes encompassing the changes in the composition of membranes and structural modifications of hemoglobin (Hb). Our results indicated that tBOOH is generally a stronger oxidizing agent than H2O2 and this observation was congruent with the activity of superoxide and glutathione peroxidase. ATR-FTIR and Raman spectroscopies of membranes revealed that tBOOH caused primarily the partial loss and peroxidation of the lipids resulting in loss of the integrity of membranes. In turn, both peroxides induced several kinds of damage in the protein layer, including the partial decrease of their content and irreversible aggregation of spectrin, ankyrin, and membrane-bound globin. These changes were especially pronounced on the membrane surface where stress conditions induced the formation of β-sheets and intramolecular aggregates, particularly for tBOOH. Interestingly, nano-FTIR spectroscopy revealed the lipid peroxidative damage on the membrane surface in both cases. As far as hemoglobin was concerned, tBOOH and H2O2 caused the increase of the oxyhemoglobin species and conformational alterations of its polypeptide chain into β-sheets. Our findings confirm that applied spectroscopies effectively track the oxidative changes occurring in the structural components of red blood cells and the simplicity of conducting measurements and sample preparation can be readily applied to pharmacological and clinical studies.

Fluorescent responsive membrane based on terbium coordination polymer and carbon dots with AIE effect for rapid and visual detection of fluoroquinolone

In this study, based on aggregation-induced emission (AIE) effect and antenna effect, a novel portable fluorescent responsive membrane was constructed with red carbon dots (R-CDs) as reference signal and terbium coordination polymer (Tb-AMP CPs) as response signal for visual, instrument-free, and sensitive detection of fluoroquinolones (FQs). Specifically, the fluorescent responsive membrane (R-T membrane) was prepared by physically depositing R-CDs with AIE property and Tb-AMP CPs on the surface of polyvinylidene fluoride filter membranes at ambient temperature. In the presence of FQs, Tb3+ in the Tb-AMP CPs of the prepared membrane coordinated with the β-diketone structure of FQs, which turned on the yellow-green fluorescence through the “antenna effect”. As the concentration of FQs increased, the R-T membrane achieved a fluorescent color transition from bright pink to yellow-green. Its visual detection sensitivity for three FQs, including ciprofloxacin, difloxacin, and enrofloxacin, was 0.01 μM, and the detection limits were 7.4 nM, 7.8 nM, and 9.2 nM, respectively, by analyzing the color parameter green. In the residue analysis of FQs in real samples, the constructed membrane also exhibited remarkable anti-interference and reliability, which is of great significance for ensuring the safety of animal-derived food.

Cysteine post-translational modifications regulate protein interactions of caveolin-3.

Caveolae are small flask-shaped invaginations of the surface membrane which are proposed to recruit and co-localize signaling molecules. The distinctive caveolar shape is achieved by the oligomeric structural protein caveolin, of which three isoforms exist. Aside from the finding that caveolin-3 is specifically expressed in muscle, functional differences between the caveolin isoforms have not been rigorously investigated. Caveolin-3 is relatively cysteine-rich compared to caveolins 1 and 2, so we investigated its cysteine post-translational modifications. We find that caveolin-3 is palmitoylated at 6 cysteines and becomes glutathiolated following redox stress. We map the caveolin-3 palmitoylation sites to a cluster of cysteines in its C terminal membrane domain, and the glutathiolation site to an N terminal cysteine close to the region of caveolin-3 proposed to engage in protein interactions. Glutathiolation abolishes caveolin-3 interaction with heterotrimeric G protein alpha subunits. Our results indicate that a caveolin-3 oligomer contains up to 66 palmitates, compared to up to 33 for caveolin-1. The additional palmitoylation sites in caveolin-3 therefore provide a mechanistic basis by which caveolae in smooth and striated muscle can possess unique phospholipid and protein cargoes. These unique adaptations of the muscle-specific caveolin isoform have important implications for caveolar assembly and signaling.

TFN nanofiltration membrane incorporating ZIF-8@MXene for efficient removal ReO4- from simulated nuclear-contaminated wastewater

In an effort to explore the potential application prospects of membrane separation technology in treating nuclear-contaminated wastewater, a TFN nanofiltration membrane incorporating the ZIF-8@Ti3C2Tx nanocomposite was successfully synthesized using the interfacial polymerization method. This involved doping the microemulsion of ZIF-8@Ti3C2Tx into the aqueous (organic) phase. The morphology and structure of ZIF-8@MXene nanocomposites and TFN nanofiltration membranes were characterized. The selective removal of ReO4- from simulated radioactive wastewater using the TFN nanofiltration membrane was evaluated. The results indicated that the ZIF-8@Ti3C2Tx composite, uniformly dispersed in the polymer, effectively enhanced the pore structure and polarity of the nanofiltration membrane, thereby improving its permeability. The electronegativity of ZIF-8@Ti3C2Tx also enhanced the negative charge on the surface of the polymer membrane, significantly improving the membrane’s performance in rejecting ReO4- while maintaining a low retention rate for Na+. This design facilitates the efficient selection of ReO4- from high-salinity wastewater. In addition, the layer spacing of Ti3C2Tx further improved the screening of ReO4- and Na+. However, when 0.75 g·L−1 of microemulsion was added, it became challenging to disperse the microemulsion completely in the organic phase. This led to the agglomeration of composites in the nanofiltration membrane, weakening both flux and selectivity. Optimal performance was achieved with a microemulsion doping amount of 0.5 g·L−1, resulting in the nanofiltration membrane M-O-1 exhibiting the best performance (Jp = 41.92 L·m2·h−1 and R(ReO4-) = 65.81%). Even at a high salt concentration (20 g·L−1), the M-O-1 membrane retained approximately 55% of pollutants after continuous operation for 5 h, indicating that the TFN nanofiltration membrane containing ZIF-8@Ti3C2Tx holds significant promise for selectively extracting 99Tc from wastewater with a high salt content.

Improving dye removal ability and fouling resistance of thin‐film nanocomposite nanofiltration membranes using a new citric acid functionalized FSM‐16 mesoporous

AbstractThe development of superior thin‐film nanocomposite (TFN) membranes with good separation performance and anti‐fouling capacity is required to address the larger‐scale freshwater need. In this study, a new citric acid‐functionalized FSM‐16 (CA‐FSM‐16) mesoporous was successfully synthesized and characterized. Subsequently, it was introduced on the surface of the sodium hydroxide/cyanuric chloride‐activated PES membrane to fabricate the CA‐FSM‐16 TFN membrane. It was investigated how various CA‐FSM‐16 loadings affected the overall physicochemical characteristics and performance of the membrane. The SEM analysis confirmed the TFN structure of the fabricated membranes. All manufactured membranes displayed improved hydrophilicity and flux. For the pristine membrane, the salt (Na2SO4) rejection was measured 73.20 ± 2.10%, whereas for the TFN‐0.08 membrane, it was measured 91.40 ± 1.80%. The dye rejection experiment in cross‐flow filtration showed that the TFN‐0.08 membrane had the maximum licorice retention among the membranes (99.10 ± 2.00%). In addition, the CA‐FSM‐16 TFN membranes demonstrated superior antifouling performance, especially the optimum membrane (TFN‐0.08), which showed a high flux recovery ratio (FRR) of 97.10 ± 1.90% and a low irreversible fouling ratio (DRir) of 2.90%. The introduction of CA‐FSM‐16 on the surface of the PES membrane via the surface modification method was a potentially useful technology to fabricate a high‐performing TFN membrane for water treatment applications.

Magnetic colloidal nanoformulations to remotely trigger mechanotransduction for osteogenic differentiation

Nowadays, diseases associated with an ageing population, such as osteoporosis, require the development of new biomedical approaches to bone regeneration. In this regard, mechanotransduction has emerged as a discipline within the field of bone tissue engineering. Herein, we have tested the efficacy of superparamagnetic iron oxide nanoparticles (SPIONs), obtained by the thermal decomposition method, with an average size of 13 nm, when exposed to the application of an external magnetic field for mechanotransduction in human bone marrow-derived mesenchymal stem cells (hBM-MSCs). The SPIONs were functionalized with an Arg-Gly-Asp (RGD) peptide as ligand to target integrin receptors on cell membrane and used in colloidal state. Then, a comprehensive and comparative bioanalytical characterization of non-targeted versus targeted SPIONs was performed in terms of biocompatibility, cell uptake pathways and mechanotransduction effect, demonstrating the osteogenic differentiation of hBM-MSCs. A key conclusion derived from this research is that when the magnetic stimulus is applied in the first 30 min of the in vitro assay, i.e., when the nanoparticles come into contact with the cell membrane surface to initiate endocytic pathways, a successful mechanotransduction effect is observed. Thus, under the application of a magnetic field, there was a significant increase in runt-related transcription factor 2 (Runx2) and alkaline phosphatase (ALP) gene expression as well as ALP activity, when cells were exposed to RGD-functionalized SPIONs, demonstrating osteogenic differentiation. These findings open new expectations for the use of remotely activated mechanotransduction using targeted magnetic colloidal nanoformulations for osteogenic differentiation by drug-free cell therapy using minimally invasive techniques in cases of bone loss.

Mitigating near-surface polarizations in membrane distillation via membrane surface decoration

Temperature and concentration polarizations near the membrane surface zone can significantly affect the performance of membrane distillation, resulting in reduced transmembrane flux and overall efficiency. The fundamental approach to mitigating near-surface polarizations involves enhancing turbulence flow near the membrane surface to minimize the formation of polarization layers. This study focuses on modifying the membrane surface via surface decoration to reduce the polarization layers. The effects of membrane surface decoration on the performance of membrane distillation were systematically investigated through an air gap membrane distillation module under various operating conditions. The hydrodynamic characteristics of the flow near the membrane surface were studied using computational fluid dynamics simulations. The characteristics of both bottom-up and top-down disturbing configurations were analyzed. In addition, we investigated the influence of various flow disturbing methods on the mass transfer coefficient in membrane distillation processes. The membrane distillation test results show that at feed temperatures of 50 °C and 70 °C, there are respective increases in transmembrane flux of 30 % and 12 %. The results provide insights into optimizing the flow state near the membrane surface for enhanced membrane distillation performance.