Potential Membrane Research Articles

Unlocking the potential of polymeric desalination membranes by understanding molecular-level interactions and transport mechanisms.

Polyamide reverse osmosis (PA-RO) membranes achieve remarkably high water permeability and salt rejection, making them a key technology for addressing water shortages through processes including seawater desalination and wastewater reuse. However, current state-of-the-art membranes suffer from challenges related to inadequate selectivity, fouling, and a poor ability of existing models to predict performance. In this Perspective, we assert that a molecular understanding of the mechanisms that govern selectivity and transport of PA-RO and other polymer membranes is crucial to both guide future membrane development efforts and improve the predictive capability of transport models. We summarize the current understanding of ion, water, and polymer interactions in PA-RO membranes, drawing insights from nanofiltration and ion exchange membranes. Building on this knowledge, we explore how these interactions impact the transport properties of membranes, highlighting assumptions of transport models that warrant further investigation to improve predictive capabilities and elucidate underlying transport mechanisms. We then underscore recent advances in in situ characterization techniques that allow for direct measurements of previously difficult-to-obtain information on hydrated polymer membrane properties, hydrated ion properties, and ion-water-membrane interactions as well as powerful computational and electrochemical methods that facilitate systematic studies of transport phenomena.

Membrane-based purification and recovery of phosphate and antibiotics by two-dimensional zeolitic nanoflakes.

The pervasive presence of persistent contaminants in water resources, including phosphate and antibiotics, has attracted significant attention due to their potential adverse effects on ecosystems and human health. Adsorption membranes packed with metal-organic frameworks (MOFs) have been proposed as a potential solution to this challenge due to their high surface area to volume ratio, and the tailored functionality they can provide for selective purification. However, devising a straightforward method to enhance the stability of MOF membranes on polymer supports and manipulate their surface morphology remains challenging. In this study, we present a facile solution immersion technique to fabricate a ZIF-L adsorption membrane on commercial supports by leveraging the self-polymerization characteristics of dopamine. The simple coating methodology provides a polydopamine-lined interface that regulates the ZIF-L heteroepitaxial growth, along with tailored nanoflake morphology. Compared with crystals prepared in bulk solution, the sorbents grown on the membrane exhibit a higher saturation capacity of 248 mg g-1 of phosphate (∼80 mg phosphorus per g sorbent) and 196 mg g-1 for tetracycline in static adsorption experiments at 30 °C. Additionally, the membranes are capable of selectively removing 99.5% of the phosphate in simulant solutions comprising competitive background ions in various concentrations, and efficiently removing tetracycline. The result from the static adsorption experiments directly translates to a flow-through process, showcasing the utility of a composite membrane with a 3 μm thick active layer in practical adsorption applications. The facile solution immersion fabrication protocol introduced in this work may offer a more efficient paradigm to harness the potential of MOF composite membranes in selective adsorption and resource recovery applications.

Single Vs Multichannel Silica-Pectin Ultrafiltration Membranes for Treatment of Natural Peat Water

A comparative study was undertaken to investigate the potential of silica-pectin ultrafiltration membrane on varied operation pressure (0.1-0.3 MPa). Cross-flow ultrafiltration works were explored with tubular alumina substrates in single and multichannel configuration. The silica-pectin sol was prepared from TEOS as silica precursor by sol-gel method, afterward pectin was templated into the silica sol to induce carbon on it. Thereafter, both of single and multichannel alumina substrates was coated by the silica-pectin sol via inner coating technique. The study exhibited better performance of multichannel silica-pectin ultrafiltration membrane (with 4 bores) compared to the single channel membrane in terms of the permeate quality of UV254 rejection, as well as the permeate flux. The UV254 rejection of multichannel silica-pectin ultrafiltration membranes conducted over 84% in compliance with highest permeate fluxes of 234.3 L.m-2.h-1.bar-1 at high operation pressure (TMP 0.3 MPa). The multichannel ultrafiltration membrane permeate flux in this work is slightly high 60-75% over single channel. Hence, both single and multichannel silica-pectin membranes exhibited steady neutralized permeate fluxes under TMP 0.3 MPa conditions for natural 100% peat water concentration, which indicates that fouling is not occurred during filtration time up to 60 min. Therefore, multichannel silica-pectin ultrafiltration membrane in this work is success to treatment of natural peat water, that the natural organic matter removal was found to be fit for uses as clean water sources.

Engineering dual-stimuli responsive poly(vinyl alcohol) nanofibrous membranes for cancer treatment by magnetic hyperthermia

The development of new cancer treatment options, such as multifunctional devices, allows for a more personalized treatment, avoiding the known severe side effects of conventional options. In this context, on-demand drug delivery systems can actively control the rate of drug release offering a precise control of treatment. Magnetically and thermally controlled drug delivery systems have been explored as on-demand devices to treat chronic diseases and cancer tumors. In the present work, dual-stimuli responsive systems were developed by incorporating Fe3O4 magnetic nanoparticles (NPs) and poly(N-isopropylacrylamide) (PNIPAAm) microgels into electrospun polymeric fibers for application in cancer treatment. First, Fe3O4 NPs with an average diameter of 8 nm were synthesized by chemical precipitation technique and stabilized with dimercaptosuccinic acid (DMSA) or oleic acid (OA). PNIPAAm microgels were synthesized by surfactant-free emulsion polymerization (SFEP). Poly(vinyl alcohol) (PVA) was used as a fiber template originating fibers with an average diameter of 179 ± 14 nm. Stress tests of the membranes showed that incorporating both microgels and Fe3O4 NPs in electrospun fibers increases their Young's modulus. Swelling assays indicate that PVA membranes have a swelling ratio of around 3.4 (g/g) and that the presence of microgels does not affect its swelling ability. However, with the incorporation of Fe3O4 NPs, the swelling ratio of the membranes decreases. Magnetic hyperthermia assays show that a higher concentration of NPs leads to a higher heating ability. The composite membrane with the most promising results is the one incorporated with DMSA-coated NPs, since it shows the highest temperature variation, 5.1 °C. To assess the membranes biocompatibility and ability to promote cell proliferation, indirect and direct contact cell viability assays were performed, as well as cell adhesion assays. Following an extract method viability assay, all membrane designs did not reveal cytotoxic effects on dermal fibroblasts and melanoma cancer cells, after 48 h exposure and support long-term viability. The present work demonstrates the potential of dual-stimuli composite membranes for magnetic hyperthermia and may in the future be used as an alternative cancer treatment particularly in anatomically reachable solid tumors.

Biological reaction mediated engineered AuNPs facilitated delivery encore the anticancer, antiglycation, and antidiabetic potential of garcinol

ObjectivesDiabetes mellitus (DM), cancer and cardiovascular diseases (CVD) are major contributors to human miseries and death. Additionally, previous findings stated that cancer is also known to be associated with diabetes. Therefore, in the given study, facile synthesis of gold nanoparticles (AuNPs) using glycation reaction was achieved and further, their bioconjugation with herbal drug garcinol (G) was performed (G-AuNPs) in order to enhance the antiglycative, antidiabetic and anticancer efficacy of the garcinol. MethodsThe antiglycation and antidiabetic potential of garcinol bioconjugated AuNPs (G-AuNPs) were assessed through different experiments. Further, anticancer potential against adenocarcinoma cells were also assessed. ResultsThe study confirmed 78.6 % bioconjugation of G over the surface of AuNPs. Furthermore, the antiglycation study depicted that G-AuNPs are found to be more effective inhibitor of the glycation reaction in contrast to pure G. The findings represented that G-AuNPs significantly blocks the formation of early glycation adducts and AGEs, also they mask the glycation prone free arginine and lysine residues from participating in the glycation process. Additionally, our α-amylase inhibition assay results demonstrated that pure G (IC50 − 8.9 µM) has significantly higher α-amylase inhibition activity compared to standard inhibitor, acarbose (IC50 − 0.118 mM). Also, the anticancer study described that G and G-AuNPs treatment resulted in death of the cells via apoptosis, which resulted in elevated permeability, condensed chromatin, deep blue fluorescent, and condensed nucleus of A549 cells. Our findings also revealed that the potential of mitochondrial membrane (ΔΨm) of A549 cells were also disrupted at much lower concentration of G-AuNPs (13.3 µM) as compared to pure G (28.7 µM). ConclusionThe key findings of the investigation suggested that G-AuNPs acted as a potent antiglycation, antidiabetic, and anticancer agent.

Application of Tissue Engineering in Manufacturing Absorbable Membranes to Improve the Osteopromoting Potential of Collagen.

The membranes are an important biomaterial that contribute to osteopromotion. This study aimed to evaluate the osteopromotive potential of collagen membranes associated with Hydroxyapatite (HA) in critical size calvaria rat's defects. Ninety-six Albinus Wistar rats were divided into four groups: (CG) negative control: clot only (CG); positive control: porcine collagen membrane (BG); fish collagen membrane associated with HA (CP); bovine collagen membrane associated with HA (CB), analyzed at 7, 15, 30, and 60 postoperative days. At 30 days, membrane integrity was observed in the CB and fragments in the CP and BG groups were dispersed in the center of the defect. At 60 days, BG demonstrated better results with no statistical difference for the CP group (p = 0.199) and a statistically significant difference for the CB group (p = 0.013). The inflammatory profiles of the BG and CP groups were similar. Immunohistochemistry demonstrated at 60 days moderate osteopontin staining for the BG and CP groups, light staining for the CB, and intense osteocalcin staining for the BG, while the CB and CP groups demonstrated moderate staining. Microtomography revealed the highest mean bone volume (14.247 mm3) in the BG, followed by the CB (11.850 mm3), and CP (9.560 mm3) group. The collagen membranes associated with HA demonstrated an osteopromotive potential.

Interaction between surfactants of different classes and nanofiltration membranes

The presence of surfactants in aquatic environments may alter the water quality parameters. Nanofiltration is a promising technique that can separate surfactants from water with high rejections. Nevertheless, negative charges on nanofiltration membranes could facilitate the occurrence of electrostatic interactions between the charged surfactants and the surface of these membranes, increasing the membrane-fouling tendency. In this work, the interaction of surfactants commonly found in residential laundry wastewater with membranes used in nanofiltration was investigated. For this purpose, the surface, and transport properties of four commercial membranes were analyzed. The zeta potential of the NF90 membrane in the presence of individual and mixture of surfactants was performed to evaluate the effect of adsorption of these surfactants on the performance of the membrane. Additionally, a central composite rotatable design (CCDR) and response surface model were applied to investigate the simultaneous effect of the initial concentration of CTAB and SDS ([CTAB + SDS]0) and pH on the NF90 permeate fluxes and rejections. It was shown that surfactant adsorption varies with the type of surfactant and membrane. Moreover, adsorption played an important role in NF90 membrane fouling, mainly for the cationic surfactant in individual solutions and in the mixture of surfactants. Besides adsorption, pore blocking may have affected the performance of nanofiltration for higher concentrations of surfactants. Finally, by the application of the central composite rotatable design (CCDR), it was possible to find the best conditions of pH and initial concentration of surfactants for achieving higher fluxes and rejections by the NF90 membrane.

Delivery of Melittin as a Lytic Agent via Graphene Nanoparticles as Carriers to Breast Cancer Cells.

Melittin, as an agent to lyse biological membranes, may be a promising therapeutic agent in the treatment of cancer. However, because of its nonspecific actions, there is a need to use a delivery method. The conducted research determined whether carbon nanoparticles, such as graphene and graphene oxide, could be carriers for melittin to breast cancer cells. The studies included the analysis of intracellular pH, the potential of cell membranes, the type of cellular transport, and the expression of receptor proteins. By measuring the particle size, zeta potential, and FT-IT analysis, we found that the investigated nanoparticles are connected by electrostatic interactions. The level of melittin encapsulation with graphene was 86%, while with graphene oxide it was 78%. A decrease in pHi was observed for all cell lines after administration of melittin and its complex with graphene. The decrease in membrane polarization was demonstrated for all lines treated with melittin and its complex with graphene and after exposure to the complex of melittin with graphene oxide for the MDA-MB-231 and HFFF2 lines. The results showed that the investigated melittin complexes and the melittin itself act differently on different cell lines (MDA-MB-231 and MCF-7). It has been shown that in MDA-MD-231 cells, melittin in a complex with graphene is transported to cells via caveolin-dependent endocytosis. On the other hand, the melittin-graphene oxide complex can reach breast cancer cells through various types of transport. Other differences in protein expression changes were also observed for tumor lines after exposure to melittin and complexes.

Proteolysis Degree of Protein Corona Affect Ultrasound-Induced Sublethal Effects on Saccharomyces cerevisiae: Transcriptomics Analysis and Adaptive Regulation of Membrane Homeostasis.

Protein corona (PC) adsorbed on the surface of nanoparticles brings new research perspectives on the interaction between nanoparticles and fermentative microorganisms. Herein, the proteolysis of wheat PC adsorbed on a nano-Se surface using cell-free protease extract from S. cerevisiae was conducted. The proteolysis caused monotonic changes of ζ-potentials and surface hydrophobicity of PC. Notably, the innermost PC layer was difficult to be proteolyzed. Furthermore, when S. cerevisiae was stimulated by ultrasound + 0.1 mg/mL nano-Se@PC, the proportion of lethal and sublethal injured cells increased as a function of the proteolysis time of PC. The transcriptomics analysis revealed that 34 differentially expressed genes which varied monotonically were related to the plasma membrane, fatty acid metabolism, glycerolipid metabolism, etc. Significant declines in the membrane potential and proton motive force disruption of membrane were found with the prolonged proteolysis time; meanwhile, higher membrane permeability, membrane oxidative stress levels, membrane lipid fluidity, and micro-viscosity were triggered.

High-performance polyethyleneimine based reverse osmosis membrane fabricated via spin-coating technology

Conventional thin-film composite (TFC) reverse osmosis (RO) membranes prepared by ultrafast and uncontrolled interfacial polymerization (IP) generally have unsatisfactory permeability and high fouling propensity, which distinctly impedes their development and wide application. Controllable thickness and roughness offer an opportunity to optimize the permeability and fouling resistance of RO membranes. In this work, we propose spin-coating assisted multilayer interfacial polymerization (SMIP) as a promising approach to fabricating high-performance RO membranes using polyethyleneimine (PEI) and 1, 3, 5-benzoyl chloride (TMC). SMIP integrates the high efficiency and uniformity of spin-coating technology, the nano-level and individual properties control of multilayer interfacial polymerization, and the simplicity of the IP process. Combining the strong hydrophilicity with low diffusion efficiency and positive charge of PEI, a thin, intrinsically hydrophilic, smoother and almost electro-neutral polyamide (PA) nanofilm was obtained. The optimal RO membrane with a controlled thickness of the selective layer (≈61 nm) has a water permeance of 3.12 L m−2 h−1 bar−1 and an acceptable NaCl rejection of 97.5%, while the strong hydrophilicity, minimal surface roughness and almost neutral surface charge afford it excellent fouling resistance. SMIP technology not only provides a new approach to preparing highly permeable and low-fouling RO membranes using macromolecular monomers, but also has great application potential in other separation membranes due to its precise control of the selective layer.

Cyclomatrix polyphosphazene organic solvent nanofiltration membranes

In this work, we report the synthesis and characteristics of cyclomatrix polyphosphazene membranes based on interfacial polymerization between 1,1-tris(4-hydroxyphenyl)ethane and hexachlorocyclotriphosphazene on top of alumina or polyacrylonitrile supports. The potential of alumina-supported thin film composite membranes as organic solvent nanofiltration membranes has been confirmed with a polystyrene-based molecular weight cutoff of 347 ± 120 Da and 503 ± 220 Da in acetone and toluene, respectively. Also, the resulting alumina-supported TFC membrane showed a methylene blue rejection (Mw = 319 g mol−1) of 98.2 ± 2.3%, 92 ± 1.7%, and 93 ± 0.5% in water, ethanol, and acetone, respectively. Furthermore, a thin film composite membrane has been prepared with a polyacrylonitrile support via interfacial polymerization to validate the preparation technique for polymeric supports and facilitate industrial implementation. The resulting membrane showed higher permeance and lower rejection than the alumina-supported membrane due to the presence of pinholes in the selective layer on top of the polyacrylonitrile supports. Our results clearly show the great potential of cyclomatrix polyphosphazene membranes as organic solvent nanofiltration membranes. However, for polyacrylonitrile-supported membranes, the preparation method needs further investigation.

Ultrafiltration as a pre-treatment technology to improve vinasse biomethanation

Vinasse is a residue that remains after the fractional distillation of fermented juice to obtain ethanol. Intended to extend the opportunities for by-product recovery, vinasse could be used as feedstock for biomethane production, departing from the linear focus of vinasse production, treatment, and disposal, to vinasse production and reuse. However, the high concentrations of sulfate and its inhibitory effect on biological activity could lower the yield of biomethane production. To overcome that, it was studied the potential of ultrafiltration membranes to alleviate the concentrations of sulfate from vinasse and concentrate the organic matter, intended to enhance the biomethane production potential. Raw vinasse, ultrafiltration concentrate, and ultrafiltration permeate were subjected to anaerobic digestion experiments and the cumulative biomethane yield was monitored over 70 days. The ultrafiltration concentrate presented the highest degradation rate (μm: 2.83 ± 0.24 mL/g-VS.d.mL-sample) and longest lag-phase time (λ: 12.31 ± 0.83 d) compared with raw sugarcane vinasse (μm: 1.44 ± 0.11 mL/g-VS.d.mL-sample; λ: 6.57 ± 0.93 d) and ultrafiltration permeate (μm: 1.14 ± 0.04 mL/g-VS.d.mL-sample; λ: 2.92 ± 0.74 d). The potential for biomethane recovery was complemented by an energetic analysis involved in biomethane production and processing. The biomethane recovery from ultrafiltration concentrate presented the lowest specific energy consumption (3.34 MJ/Nm³-CH4), followed by raw sugarcane vinasse (3.51 MJ/Nm³-CH4) and ultrafiltration permeate (3.64 MJ/Nm³-CH4). The remaining digested streams could still be potentially applied to soils for better use of their nutrients, however without an excessive load of organic matter already consumed during anaerobic digestion. Overall, the study demonstrated an effective alternative to salinity relief in raw sugarcane vinasse by ultrafiltration membranes and an alternative of higher vinasse valorization.

Spontaneous and Electrically Induced Anisotropy of Composite Agarose Gels.

Agarose gels containing and not bacteriorhodopsin purple membranes (incorporated before gelling) manifest spontaneous optical anisotropy. The dependencies of the anisotropy on the agarose concentration and time have been studied. The rise in the anisotropy is explained by the predominant orientation of the agarose fibers during the gelling and subsequent deformation of the gel net. In the electric field, additional optical anisotropy rises, which is caused by the orientation of the membranes. A procedure has been developed to separate electrically induced and spontaneous anisotropy in composite gels. The isoelectric points and surface electric potential of bacteriorhodopsin trimer and purple membranes are calculated by the method of protein electrostatics to explain their electric asymmetry, which leads to perpendicular orientation in the direct electric field and longitudinal in the kilohertz sinusoidal field. The results allow for an increase in the separation capability of composite gels of electrophoresis for macromolecules with different sizes by applying an appropriate electric field to modulate the effective pore size.

Effect of non-stoichiometry of KxFe[Fe(CN)6] as inner solid-contact layer on the potential response of all-solid-state potassium ion-selective electrodes

In the current study, we synthesized Prussian blue analogues, KxFe[Fe(CN)6] (KFeHCF) having different [Fe(CN)6] vacancies, potassium contents (x), and crystal system, and investigated the effect of the difference on ion-sensor performance by using the KFeHCF as the solid-contact layer of all-solid-state ion-selective electrodes (ASS-ISEs). Cubic-KFeHCF shows slopy potential curve during galvanostatic K+ extraction/insertion because the reaction proceeds in single-phase regime, which deteriorates the long-term potential stability as internal reference electrode of ASS-ISEs. On the other hand, monoclinic-KFeHCF exhibits flat potential plateau during galvanostatic K+ extraction/insertion through two-phase reaction, providing superior potential stability. While the potential of an ISE is primarily determined by the membrane potential of the ion-sensitive membrane, it is discovered that the different crystal structure of the KFeHCF introduced into the solid-contact layer affects the long-term stability of ISE.

Multifunctional terahertz microscopy for biochemical and chemical imaging and sensing

Laser-excited terahertz emission microscopy (LTEM) has exhibited great potential for studying the dynamic physical properties of various materials and device evaluation. In this study, an up-to-date version of LTEM, the terahertz chemical microscopy, was developed for biochemical and chemical imaging and sensing. By functionalizing a terahertz semiconductor emitter with an ion-sensitive membrane, a DNA aptamer, and a specific polymer, the change in the terahertz signal amplitude attributed to the surface electrical potential change was successfully detected. Accordingly, the measurement of calcium ions (Ca2+), stress biomarker cortisol, and 2, 4, 6-trinitrotoluene (TNT) explosive was achieved. Measured of charged Ca2+ was via the change in the electrical potential of the ion-sensitive membrane with ion accumulation. For non-charged cortisol and TNT measurements, the surface potential change was recorded by the conformational change of the negatively charged DNA aptamer bound to cortisol and the charge-transfer complex formation between TNT and polyethylenimine polymer, respectively. Moreover, the specificity of this sensing approach was demonstrated by molecular docking and measuring the interfering substances such as sodium ions, potassium ions, brain chemicals histamine and dopamine, and TNT analogues. The results showed that the developed multifunctional terahertz microscopy technique can be used for trace biochemical and chemical sensing via visualization of the terahertz amplitude distribution.

Биоэлектрические эффекты отмывания клеток Сhara fragilis от растворов фитокомпозиции одуванчик-зверобой-календулы

By using of microelectrode techniques, patterns of change in the potential (φm) and resistance (Rm) of the plasma membrane (PM) of Chara fragilis cells under the influence of Dandelion–Hypericum-Calendula (DHC) phytocomposition solutions were studied. The values of φm and Rm are widely scattered: -90 ÷ -300 mV and 1 ÷ 32.6 Ohm·m2, respectively under the standard conditions. The average value of φm was -183 ± 4.9 mV, Rm = 9.2 ± 1.2 Ohm·m2. Using the dependences of φm, Rm on the concentration of K+ in the external environment, the ranges of activation of the K+ - channels to the inward (KCİR) and outward rectification (KCOR) were determined. Under the action of the DHC phytocomposition, while the cell was in the medium with the concentration of the composite 10-1 or 1 mg/ml, we did not detect changes in φm and Rm for 25 min. Stimulation or suppression of transport processes under the influence of composites occurred only with the exclusion of DHC from the composition of the nutrient medium and with a stepwise increase in the concentration of the composition in the medium. The electrophysiological effects of the action of the DHC composition are discussed from the point of view of its action on the lipid phase of the plasma membrane of the experimental cells.

Graphitic carbon nitride assisted PVDF-HFP based solid electrolyte to realize high performance solid-state lithium metal batteries

Solid polymer electrolyte (SPE) is routinely regarded as core component to tackle the potential safety hazards and energy density of conventional lithium-ion batteries. However, it is still beset by low ionic conductivity and poor interface compatibility. Currently, the utilization of SPEs to replace flammable and leaky liquid electrolytes is regarded as a powerful method to promote battery security. However, it is still an arduous task to develop a SPE with a wider electrochemical window and higher ionic conductivity. Herein, graphitic carbon nitride (g-C3N4) nanosheets were prepared by thermal oxidative exfoliation and introduced into PVDF-HFP based SPEs to prepare solid composite electrolyte for the first time. The introduction of g-C3N4 nanosheets effectively disrupts the orderly arrangement of polymer segments in the SPE, thereby diminishing the crystallinity of the solid electrolyte. The results prove that the presence of g-C3N4 nanosheets efficiently reduces the bulk impedance of the solid electrolyte membrane, enhance the ionic conductivity and ion transport number, and boost the oxidation potential and stability of the electrolyte membrane to the lithium anode. The ionic conductivity of SPE with 15 wt% g-C3N4 nanosheets is 1.67 × 10−4 S·cm−1 at 25 °C, and its oxidation potential reaches 4.7 V. The NCM622/PCSE3/Li battery delivered a specific discharge capacity of 122.8 mAh·g−1 after 100 cycles at 0.5 C.

Histological and Molecular Evidence of the Positive Performance of Glycerol-Plasticized Chitosan-Alginate Membranes on Skin Lesions of Hyperglycemic Mice.

The purpose of this study was to investigate tissue repair of excisional wounds in hyperglycemic animals treated with chitosan-alginate membranes (CAM) produced in the presence of glycerol. 8-week C57B1 male mice were divided into normoglycemic animals with a 0.9% saline solution topical treatment (CTSF); hyperglycemic animals with 0.9% saline solution topical treatment (DMSF) and hyperglycemic animals with glycerol-plasticized chitosan-alginate membrane topical treatment (DMCAM). On post-wound day three, the DMCAM group presented a lower number of leukocytes, mature mastocytes, a higher number of vessels (p < 0.05), and active mastocytes (p < 0.05) when compared to the CTSF and DMSF groups. There were no differences regarding the distribution, deposition, organization, and thickness of collagen fibers. On day 7 there were no differences in the analysis of fibroblasts, mastocytes, and TGF−β1 and VEGF expressions among the groups. Regarding collagen fibers, the DMCAM group presented slight red-orange birefringence when compared to the CTSF and DMSF groups. On day 14 there was a slight concentration of thinner elastic fibers for the DMCAM group, with a greater reorganization of papillary skin and improved red-orange birefringence collagen fibers, as well as net-shaped orientation, similar to intact skin. In addition, improved elastic fiber organization distributed in the entire neo-dermis and a larger presence of elaunin fibers were observed, in a similar pattern found in the intact skin. The use of CAM in cutaneous lesions boosted tissue repair since there was a smaller number of inflammatory cells and mastocytes, and an improvement in collagen deposition and collagen fibers. These results demonstrate the high potential of plasticized chitosan-alginate membrane for skin wound dressing of hyperglycemic patients.

Fabrication of novel hydrophobic electrospun nanofiber membrane using polybenzoxazine for membrane distillation application

In this study, a novel hydrophobic blend polyvinylidene fluoride (PVDF) nanofibrous membrane with polybenzoxazine (PBz) was fabricated by the electrospinning technique to apply in membrane distillation (MD) process. Accordingly, pristine PVDF and a fluoro containing benzoxazine monomer (Bz) was blended and then thermally treated for crosslinking the Bz. The membrane properties were determined in terms of contact angle, young module, thickness, and the membranes were characterized by scanning electron microscope and Fourier transform infrared spectroscopy. The water contact angle of membranes increased from ca. 102.8° for the pristine PVDF membrane to 132.7° post cured Bz blended membrane. Moreover, the mechanical properties of blended membranes enhanced, while obtaining smoother and physically more stable membranes compared to the pristine nanofibrous membrane. The optimum membranes were tested in a lab-scale vacuum assisted air gap membrane distillation system. Results showed that Bz blended and cured membranes exhibited higher rejections and permeate flux for reverse osmosis brine and boron solutions compared to the pristine membrane that demonstrate the promising potential of Bz blended membranes in MD applications.

Boosting the Performance of Nanofiltration Membranes in Removing Organic Micropollutants: Trade-Off Effect, Strategy Evaluation, and Prospective Development.

In view of the high risks brought about by organic micropollutants (OMPs), nanofiltration (NF) processes have been playing a vital role in advanced water and wastewater treatment, owing to the high membrane performance in rejection of OMPs, permeation of water, and passage of mineral salts. Though numerous studies have been devoted to evaluating and technically enhancing membrane performance in removing various OMPs, the trade-off effect between water permeance and water/OMP selectivity for state-of-the-art membranes remains far from being understood. Knowledge of this effect is significant for comparing and guiding membrane development works toward cost-efficient OMP removal. In this work, we comprehensively assessed the performance of 88 NF membranes, commercialized or newly developed, based on their water permeance and OMP rejection data published in the literature. The effectiveness and underlying mechanisms of various modification methods in tailoring properties and in turn performance of the mainstream polyamide (PA) thin-film composite (TFC) membranes were quantitatively analyzed. The trade-off effect was demonstrated by the abundant data from both experimental measurements and machine learning-based prediction. On this basis, the advancement of novel membranes was benchmarked by the performance upper-bound revealed by commercial membranes and lab-made PA membranes. We also assessed the potentials of current NF membranes in selectively separating OMPs from inorganic salts and identified the future research perspectives to achieve further enhancement in OMP removal and salt/OMP selectivity of NF membranes.