Potential Membrane Research Articles

Bi-layered nanofibrous membrane with osteogenic and antibacterial functions for periodontal tissue regeneration.

Guided tissue regeneration (GTR) membranes have great potential to promote periodontal tissue regeneration and reestablishment. However, the regeneration potential and microbial infection resistance of current GTR membranes still need to be improved. Here, a bi-layered nanofibrous membrane on the basis of poly (lactic-co-glycolic acid) (PLGA)/gelatin with osteogenic and antibacterial functions was fabricated for periodontal tissue regeneration. The antimicrobial layer (AL) of the bi-layered nanofibrous membrane was composed of nanofibrous PLGA/gelatin nanofibers loaded with nano-silver (nAg), while the osteoconductive layer (OL) of the nanofibrous membrane consisted of PLGA/gelatin nanofibers loaded with nano-hydroxyapatite (nHA). The bi-layered nanofibrous membrane was examined by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS) and X-ray diffractometry (XRD). The results showed that nHA and nAg particles were well evenly loaded or embedded in PLGA/gelatin nanofibers. The cell culture experiments suggested that the bi-layered nanofibrous membrane possessed good cytocompatibility and the OL of the bi-layered nanofibrous membrane possessed an enhanced osteogenic capacity for human osteoblast-like cells (MG63), which was verified by the good cell viability and the increased alkaline phosphatase (ALP) activity, respectively. The results of in vitro antimicrobial study displayed that the AL of the bi-layered nanofibrous membrane possessed an effective antibacterial capability. In conclusion, the prepared bi-layered nanofibrous membrane with osteogenic and antibacterial functions may have great potential for periodontal tissue regeneration and reestablishment.[Formula: see text].

Photocatalytic Filtration of Zinc Oxide-Based Membrane with Enhanced Visible Light Responsiveness for Ibuprofen Removal

The growing interest in mixed matrix membranes (MMMs) for developing photocatalytic membranes has provided a new direction in the search for efficient methods to concurrently separate and degrade contaminants. In this study, a visible light-responsive photocatalyst was blended into a polyvinylidene fluoride (PVDF) membrane casting solution to prepare PVDF-ZnO/Ag2CO3/Ag2O MMMs using the wet phase inversion method. The potential of ZnO/Ag2CO3/Ag2O as a photocatalytic component that is incorporated into the membrane was explored in detail under various loadings (0.5–2.91 wt%). The membranes were tested under ibuprofen (IBF) aqueous solution to analyze the membrane behavior in the synergistic combination of membrane filtration and photodegradation. The resulting PVDF-ZnO/Ag2CO3/Ag2O membrane with a rougher membrane surface area and excellent light harvesting capability showed higher photocatalytic filtration activity in removing IBF under visible light irradiations. The MMM fluxes demonstrated higher IBF fluxes than their initial fluxes at certain durations. This indicates that the membrane actively responds to light irradiation. The increase in the positive flux could be attributed to the photoinduced hydrophilicity generated by the ZnO/Ag2CO3/Ag2O photocatalyst, resulting in easier water layer formation and rapid transport through membranes. The highest IBF removal was demonstrated by the PVDF-ZAA2 membrane (1.96 wt% loading), with 49.96% of IBF removal within 180 min upon visible light irradiation. The reason for this lower IBF removal is that the UF membrane pores exceed the size of IBF molecules, thereby preventing the size exclusion mechanism. Thus, charge repulsion, hydrophobic adsorption, and photocatalytic activity were considered along with the IBF removal of the photocatalytic membranes. However, the recyclability of the PVDF-ZAA2 photocatalytic membrane showed a great improvement, with 99.01% of IBF removal recovery after three cycles. These results highlight the potential of such hybrid membranes in mitigating membrane fouling by providing a platform for photocatalysts to continuously degrade pollutants present in such wastewaters. Therefore, the hybridization of a photocatalyst and membrane provides insight that could be utilized to improve and retrofit current water effluent treatment methods.

Insights into the progress of polymeric nano-composite membranes for hydrogen separation and purification in the direction of sustainable energy resources

• The review discusses over various membrane engineering methods. • Use of new and advanced membrane materials for improving the separation. • Concept of mixed matrix membranes for better separation efficiency are also elaborated. • An effective comparison between the separation data and type of membranes is also discussed using the Robeson upper bound. The industrial gas hydrogen has showcased its utility in a variety of processes, including those in the steel and petrochemical industries. However, synthetically produced hydrogen contains other impurities and some unreacted substituents like CO 2 , N 2 , CH 4 , etc. that needs to stamp out. For this purpose, efficient and environmentally friendly, polymer membrane technology provides tremendous potential. The core objective of this paper is to analyze several key rules regarding material engineering and the separation mechanism used for the betterment of hydrogen separation membranes. In this review, we have highlighted the ongoing research using different polymer membrane materials to design matrices with better characteristics than the previous one. We have focused on different polymers which are involved as the main matrix while a variety of organic/inorganic particles are appended in the role of fillers to conquer the well-established trade-off. The principle criteria’s are- (1) the phenomenology and regularities of hydrogen transfer through polymeric membranes, and (2) polymer membrane materials with favourable hydrogen separation properties in terms of permeability and selectivity. The results from the critical analysis of the published data over the potential of polymeric membranes towards hydrogen separation are also discussed. Furthermore, as per the conclusions of a thorough review, these polymer nanocomposite membranes can compete with or eventually replace the conventional approaches.

Conductive reverse osmosis membrane for electrochemical chlorine reduction and sustainable brackish water treatment

The susceptibility of RO membrane for chlorine, which is widely used for disinfecting the feedwater, remains a biggest challenge. Herein for the first time, we report an electrochemical chlorine reduction on a conductive RO membrane interface as a sustainable solution to overcome this limitation. In this study, cyclic voltammetry was employed to investigate the potential of electrochemical chlorine reduction. Later, a conductive RO membrane with an embedded carbon nanotubes layer (CNT-RO) was fabricated, and its resistance to chlorine was tested via batch soaking into a sodium hypochlorite solution (NaOCl; 1,000 ppm; pH = 5) used as the chlorine source, followed by the flux and salt rejection monitoring.The CNT-RO membrane resulted in 3.5% and 9.3% chlorine uptake after chlorinating for 1 h and 24 h, hence faced prominent decline in the amide II and aromatic amide peak positioned at 1541 cm−1 and 1609 cm−1, respectively. In contrast, the application of 2 V on conductive CNT-RO membrane interface when used as a cathode resulted in an irreversible chlorine reduction, hence formed chloride as validated via ion chromatography. Chlorination of CNT-RO membrane under conducting mode could not cause any significant change in the membrane morphology, elemental composition, amide bonding structure, and surface wettability. Therefore, CNT-RO membrane demonstrated 88% rejection against monovalent salt even after 24 h of chlorination under conducting mode as compared to the commercial and CNT-RO (chlorinated without DC charge application) which showed 69% and 74% rejection, respectively. These findings clearly illustrated the potential of conductive RO membrane for sustainable desalination and water reuse applications.

Simultaneous retention of organic and inorganic contaminants by a ceramic nanofiltration membrane for the treatment of semiconductor wastewater

The semiconductor manufacturing industry produces large amounts of ammonia-contaminated wastewaters which require costly and energy-intensive treatments. This study demonstrates the application of a commercially available ceramic nanofiltration (NF) membrane for the control of organic and inorganic contaminants as well as ammonium retention in the treatment of semiconductor wastewater. Analysis of the hydrodynamic pore transport model based on the direct measurement of membrane thickness in the active layer indicated that the ceramic NF membrane has an average pore radius of ≈0.65 nm. Zeta potential measurements of the ceramic NF membrane showed that the membrane surface was negatively charged at neutral pH. The ammonium retention capacity of the ceramic NF membrane was evaluated using a single symmetric ammonium salt solution (1.8 mM NH4HCO3; i.e., the average ammonium concentration in semiconductor wastewater) and combined salt solutions (mixtures of 1.8 mM NH4HCO3 and either 2.0 mM of Na2SO4, CaSO4, or CaCl2). The combined NH4HCO3 and Na2SO4 solution rendered a remarkably high ammonium retention rate of 88.7%, which was attributed to higher valency co-ions (SO42-) in this solution with the same negative surface charge of the ceramic NF membrane. In contrast, the calcium ions (Ca2+) in different combined salt solutions containing CaSO4 and CaCl2 interfered with ammonium retention. We further employed the ceramic NF membrane to treat semiconductor wastewater samples taken from a full-scale semiconductor wastewater treatment plant and demonstrated that this proposed treatment method could effectively retain organic and inorganic contaminants with a low fouling propensity. Our results highlight the promising potential of ceramic NF membranes for the treatment of industrial wastewaters with diverse organic and inorganic contaminants.

Pilot-Scale Test Results of Electrodialysis Bipolar Membrane for Reverse-Osmosis Concentrate Recovery.

In this study, it is aimed to investigate the potential of electrodialysis bipolar membrane (EDBM) systems for the recovery of the concentrate originating from an organized industrial estate (OIE) wastewater treatment system with reverse osmosis (RO). Acids and bases were obtained from a pilot-scale treatment plant as a result of the research. Furthermore, the sustainability and affordability of acids and bases obtained by EDBM systems were investigated. Six cycles were carried out in continuous-flow mode with the EDBM system as batch cycles in the disposal of the concentrate and the production of acids and bases with the EDBM system. For each cycle, the EDBM system was operated for 66, 48, 66, and 80 min, respectively, and the last two cycles were operated for a total of 165 min (70 + 90) with 5 min of waiting. In the EDBM system, a working method was determined such that the cycle flow rate was 180 L/hour, energy to be given to the system was 25 V, and the working pressure was in the range of 0.8–2.5 bar. In the six cycles with the EDBM system, the concentrate, acid and base, conductivity, pH, and pressure increase values were investigated depending on time. Throughout all these studies, the cycles were continued over the products formed in the acid and base chamber. As a result of all the cycles, acid (HCl) production at a level of 1.44% and base (NaOH) production at a level of 2% were obtained.

Comparison of Efficacy and Patient Response Between 2% Lidocaine and 4% Articaine during Routine Dental Extractions

Introduction: Local Anaesthetic (LA) agents are chemicals that reversibly block the transmission of action potential of nerve membrane. Lidocaine has established itself as the gold-standard owing to its excellent clinical properties with minimal side effects. Articaine, a relatively newer LA agent is reported to have better clinical properties than Lidocaine. Aim: To compare and evaluate the differences in total volume of LA agent used, onset of subjective symptoms and objective signs, total duration of anaesthesia achieved and postoperative pain assessment with 2% lidocaine and 4% articaine during routine dental extractions. Materials and Methods: This randomised clinical study was conducted by the Department of Dentistry, Sri Krishna Medical College and Hospital, Muzaffarpur, Bihar, India from October 2020 to February 2021. A total of 200 patients (107 females and 93 males) requiring mandibular molar extraction were included in the study. The patients were randomly divided into two study groups. group-1 patients were administered with 2% lidocaine while Group-2 patients were administered with 4% articaine. Complete demographic and clinical details of all the patients were recorded. The volume of LA agent used, onset time for subjective symptoms and objective signs and total duration of anaesthesia was recorded. Postoperative pain was recorded on Visual Analogue Scale (VAS) on a scale of 0 to 10. All the variables were recorded in Microsoft excel sheet and were analysed by SPSS version 21 software. A two-tailed p-value less than 0.05 (p<0.05) was considered statistically significant. Results: A total of 200 patients participated in the study, where group-1 patients (49 males and 51 females) had a mean age of 34.79±10.43 years and group-2 patients (44 males and 56 females) had a mean age of 35.41±11.39 years. Statistically insignificant differences (p>0.05) were obtained for the following parameters–volume of LA agent used, onset time of subjective symptoms, onset time of objective signs and postoperative VAS scores. A statistically significant difference (p<0.05) was observed for total duration of anaesthesia. Conclusion: Both 2% lignocaine and 4% articaine are equally effective LA agents in patients undergoing mandibular molar extractions. However, 2% articaine exhibited significantly higher duration of total anaethesia when compared to 2% lidocaine.

Human amniotic membrane extracellular matrix scaffold for dental pulp regeneration in vitro and in vivo.

In order to obtain a 3-dimentional scaffold with predictable clinical results for pulp regeneration, this study aims to fabricate and characterize a porous decellularized human amniotic membrane (HAM) extracellular matrix (ECM) scaffold, and evaluate its potential to promote pulp regeneration in vitro and in vivo. The HAM was decellularized, and its histology and DNA content were analysed to confirm decellularization. The scaffolds were synthesized with 15, 22.5 and 30mg/ml concentrations. The porosity, pore size, phosphate-buffered saline (PBS) absorption and degradation rate of the scaffolds were assessed. In vitro experiments were performed on human dental pulp stem cells (hDPSCs) to assess their viability, proliferation, adhesion and migration on the scaffolds. The optimal group was selected for in vivo immunogenicity assessment and was also used as the cell-free or cell-loaded scaffold in root segment models to evaluate pulp regeneration. All nonparametric data were analysed with the Kruskal-Wallis test followed by Dunn's post hoc test, whilst quantitative data were analysed with one-way anova. Decellularization of HAM was confirmed (p<.05). The porosity of all scaffolds was more than 95%, and the pore size decreased with an increase in ECM concentration (p<.01). PBS absorption was not significantly different amongst the groups, whilst 30mg/ml ECM scaffold had the highest degradation rate (p<.01). The hDPSCs adhered to the scaffold, whilst their proliferation rate increased over time in all groups (p<.001). Cell migration was higher in 30mg/ml ECM scaffold (p<.05). In vivo investigation with 30mg/ml ECM scaffold revealed mild to moderate inflammatory response. In root segments, both cell-free and cell-loaded 30mg/ml scaffolds were replaced with newly formed, pulp-like tissue with no significant difference between groups. Immunohistochemical assessments revealed high revascularization and collagen content with no significant difference amongst the groups. The 30mg/ml HAM ECM scaffold had optimal physical properties and better supported hDPSC migration. The HAM ECM scaffold did not interfere with formation of pulp-like tissue and revascularization within the root canal when employed as both cell-free and cell-loaded scaffold. These results highlight the potential of HAM ECM membrane for further investigations in regenerative endodontics.

Renewable energy powered membrane technology: Energy consumption analysis of ultrafiltration backwash configurations

In the field of ultrafiltration (UF) membranes for water treatment, fouling is a severe problem that limits the potential of the technology UF membranes and results in increased energy consumption. In this study, a small-scale photovoltaic-powered membrane system was employed to investigate the energy consumption of two UF backwashing configurations – a bladder tank and a backwash (BW) pump powered by supercapacitors – under varied solar irradiance conditions. Fouling was induced via the addition of bentonite, and then examined at varied BW intervals using the bladder tank to optimize the total specific energy consumption (TSEC) – determined for both UF BW and reverse osmosis (RO) desalination processes. Simulated fouling – realized via a pressure drop across a ball valve – was proposed to induce inorganic fouling without requiring the addition of foulants. The TSEC of both bentonite and simulated fouling was compared. Under simulated fouling and constant solar irradiance operating conditions, the bladder tank exhibits a BW SEC of 0.3 Wh/L, while the BW pump exhibits SEC of 0.09Wh/L. The TSEC is maintained at ∼ 4 Wh/L under varied real “solar days” with the bladder tank, indicating that the energetic penalty for implementing one BW cycle every 90 min is small. A BW interval of 60 min exhibited a TSEC of 3.7 Wh/L and provided a good compromise between TSEC and the mitigation of membrane fouling. The concept of using a valve to simulate fouling in the system can assist with the UF membrane fouling studies without inducing irreversible fouling to the membrane. Despite its higher BW SEC, the bladder tank was a more robust setup and is recommended for adding BW functionality to renewable-energy powered membrane filtration systems.

Increased ion transport and high-efficient osmotic energy conversion through aqueous stable graphitic carbon nitride/cellulose nanofiber composite membrane

Increased attention has evoked on the utilization of renewable energy, particularly osmotic power as a potential solution to the energy crisis and environmental pollution. Herein, we fabricate graphitic carbon nitride (g-C3N4)/cellulose nanofiber (CNF) composite membranes with tailored lamellar nanochannels for capturing osmotic energy from salinity gradients. Composite membranes exhibiting charge-governed ion conductivity were prepared via co-homogenization of g-C3N4 with CNF and vacuum filtration. Ion conductivity was efficiently modulated by fine-tuning the charge density through controlling the weight content of CNF in the composite membranes. Higher ion conductivity of 0.014 S cm−1 at low concentrations (<10−2 M KCl) was achieved due to the increased charge density of the lamellar nanochannels and the excellent aqueous stability of the membranes. We demonstrate the potential of the composite membranes in nanofluidic osmotic energy conversion, displaying thermo-enhanced power output performance. This work could inspire new designs of cellulose-based nanofluidic devices for improved osmotic energy conversion.

High Indirect Energy Consumption in AEM-Based CO2 Electrolyzers Demonstrates the Potential of Bipolar Membranes.

Typically, anion exchange membranes (AEMs) are used in CO2 electrolyzers, but those suffer from unwanted CO2 crossover, implying (indirect) energy consumption for generating an excess of CO2 feed and purification of the KOH anolyte. As an alternative, bipolar membranes (BPMs) have been suggested, which mitigate the reactant loss by dissociating water albeit requiring a higher cell voltage when operating at a near-neutral pH. Here, we assess the direct and indirect energy consumption required to produce CO in a membrane electrode assembly with BPMs or AEMs. More than 2/3 of the energy consumption for AEM-based cells concerns CO2 crossover and electrolyte refining. While the BPM-based cell had a high stability and almost no CO2 loss, the Faradaic efficiency to CO was low, making the energy requirement per mol of CO higher than for the AEM-based cell. Improving the cathode–BPM interface should be the future focus to make BPMs relevant to CO2 electrolyzers.

Combining Coaxial Electrospinning and 3D Printing: Design of Biodegradable Bilayered Membranes with Dual Drug Delivery Capability for Periodontitis Treatment.

Periodontitis is a chronic inflammatory disease that can lead to significant destruction of tooth-supporting tissues, compromising dental function and patient's health. Although the currently employed treatment approaches can limit the advance of the disease, the development of multifunctional and hierarchically structured materials is still in demand for achieving successful tissue regeneration. Here, we combine coaxial electrospinning and 3D printing techniques to prepare bilayered zein-based membranes as a potential dual drug delivery platform for periodontal tissue regeneration. A layer of core-sheath electrospun nanofibers consisting of poly(ethylene oxide) (PEO)/curcumin (Curc)/tetracycline hydrochloride (TH) as the core and zein/poly(ε-caprolactone)(PCL)/β-glycerolphosphate (β-GP) as the sheath was deposited over a 3D printed honeycomb PLA/zein/Curc platform in order to render a bilayered structure that can mimic the architecture of periodontal tissue. The physicochemical properties of engineered constructs as well as the release profiles of distinct drugs were mainly controlled by varying the concentration of zein (10, 20, 30%, w/w relative to dry PCL) on the sheath layer of nanofibers, which displayed average diameters ranging from 150 to 400 nm. In vitro experiments demonstrated that the bilayered constructs provided sustained release of distinct drugs over 8 days and exhibited biocompatibility toward human oral keratinocytes (Nok-si) (cell viability >80%) as well as antibacterial activity against distinct bacterial strains including those of the red complex such as Porphyromonas gingivalis and Treponema denticola, which are recognized to elicit aggressive and chronic periodontitis. Our study reveals the potential of zein-based bilayered membranes as a dual drug delivery platform for periodontal tissue regeneration.

Changes in the compound zeta potential of erythrocyte membranes in patients with arterial hypertension and obesity

The development of microcirculatory disorders is considered to be one of the earliest changes in the cardiovascular system with a combination of arterial hypertension (AH) and obesity. The rheological properties of blood play a significant role in the system of microcirculation. An important place in changing the rheological characteristics of blood is largely assigned to erythrocytes. Aggregation of erythrocytes is closely related to the magnitude of the surface-bound charge of their membranes or zeta potential of erythrocyte membranes. Purpose. To study the state of compound zeta potential of erythrocyte membranes in patients with hypertension and obesity. Material and methods. The study included 112 patients with AH and Index of Mass Corporal more than 30 kg/m2 (main group); the control group consisted of 25 people without AH and obesity. All patients of the main group received standard antihypertensive, lipid-lowering and hypoglycemic therapy to achieve the target levels of the indices under correction. Results. The level of compound zeta potential of erythrocyte membranes in patients with AH and obesity was significantly lower than in the control group and amounted to 1.57 ± 0.06 × 107 and 1.67 ± 0.03 × 107, respectively (p &lt; 0.05). At the same time, in patients of the main group with an increase in AH, lower indices were noted. In patients with AH and obesity, a significant inverse correlation was found between the compound zeta potential of erythrocyte membranes and the degree of hypertension, which indicates a negative effect of hypertension on the rheological properties of blood at the microvasculature level. A correlation analysis was carried out to evaluate the association between Index of Mass Corporal and zeta potential of erythrocyte membranes in obese hypertensive patients. A negative direct correlation was revealed (r = 0.7, p &lt; 0.05). Conclusion: a decrease in the total charge of erythrocytes can be considered as an early sign of microrheological disorders in patients with a controlled course of arterial hypertension and obesity.

Ultralight ethyl cellulose-based electret fiber membrane for low-resistance and high-efficient capture of PM2.5

Atmospheric particulate matter (PM) pollution is a serious threat to human health, so the preparation of electret films with high efficiency and low resistance capturing particulate has attracted wide attention. Herein, a strategy for the fabrication of all-polymer hybrid electret fiber membranes by electrospinning is reported based on the ethyl cellulose (EC) and polystyrene (PS). The preparation conditions of electret fiber membrane were optimized by focusing on the effect of the mass ratio of EC/PS and the spinning time on the structure, surface potential and purification performance of fiber membrane. The result showed that the fiber membrane has a low fiber diameter of 572 ± 113 nm and porosity of 82.4%, and a better potential stability when the EC/PS mass ratio was 2.5/1 and the spinning time was 10 min. As a result of the enhanced effect of electrostatic attraction on particle capture, the EC/PS composite electret membrane could make the purification efficiency of PM2.5 reach to100% within 11 min. Moreover, the EC/PS composite electret membrane has the properties of ultra-light base weight of 1.08 g·m −2 , low air resistance of 28 Pa and long service life. Therefore, the all-polymer EC/PS electret nanofiber membranes have broad application prospects in the field of air purification. • All-polymer electret EC/PS fibers without nanotoxicity are prepared. • Biomass-based electret based on ethyl cellulose as the main raw material increases the environmental friendliness of the material. • the fabricated electret fiber has an ultralight base weight. • the resultant electret fibers with high efficiency and low resistance can be compared with high efficiency air purification membrane.

Self-Healing of a Covalently Cross-Linked Polymer Electrolyte Membrane by Diels-Alder Cycloaddition and Electrolyte Embedding for Lithium Ion Batteries.

Thermally reversible self-healing polymer (SHP) electrolyte membranes are obtained by Diels-Alder cycloaddition and electrolyte embedding. The SHP electrolytes membranes are found to display high ionic conductivity, suitable flexibility, remarkable mechanical properties and self-healing ability. The decomposition potential of the SHP electrolyte membrane is about 4.8 V (vs. Li/Li+) and it possesses excellent electrochemical stability, better than that of the commercial PE film which is only stable up to 4.5 V (vs. Li/Li+). TGA results show that the SHP electrolyte membrane is thermally stable up to 280 °C in a nitrogen atmosphere. When the SHP electrolyte membrane is used as a separator in a lithium-ion battery with an LCO-based cathode, the SHP membrane achieved excellent rate capability and stable cycling for over 100 cycles, and the specific discharge capacity could be almost fully recovered after self-healing. Furthermore, the electrolyte membrane exhibits excellent electrochemical performance, suggesting its potential for application in lithium-ion batteries as separator material.

Exploring the feasibility of novel double-skinned forward osmosis membranes with higher flux and superior anti-fouling properties for sludge thickening

Sludge thickening from sewage treatment plants is an essential step in reducing the sludge volume and processing cost of the subsequent treatment. Forward osmosis (FO) technology is one of the research endeavors used in the field of membrane separation and feed solution concentration. However, the traditional used single-skinned FO membranes encounter the problems of serious internal concentration polarization (ICP) and fouling phenomenon within porous substrates. A novel double-skinned FO membrane was proposed in this study in order to enhance the anti-fouling performance and mitigate the ICP phenomenon. Single-skinned FO membrane using the same substrate was also fabricated. Results demonstrated that the double-skinned FO membrane significantly reduced ICP and exhibited higher flux when using draw solutions with high concentrations as compared to the single-skinned FO membrane. Furthermore, the double-skinned FO membrane demonstrated reasonably high-water flux (11.6 LMH), whereas zero flux was recorded from the single-skinned FO membrane when using the feed solution that contained 15.0 g/L organic foulants in the fouling tests. At last, the double-skinned FO membrane exhibited superior anti-fouling properties and much higher flux than that of single-skinned FO membrane operated under both modes during the long-term sludge thickening process, indicating the great potential of the double-skinned FO membrane to deal with the high-water-content sewage sludge in the water treatment process.

Phosphodiesterase Type 5 Inhibitors Greatly Affect Physicochemical Properties of Model Lipid Membranes.

Although phosphodiesterase type 5 inhibitors are widely used and well-studied drugs, the potential benefits of their application in the treatment of various diseases and new drug delivery systems, including liposome forms, are still being discussed. In this regard, the role of the lipid matrix of cell membranes in the pharmacological action of the inhibitors is of special interest. It was shown that sildenafil, vardenafil, and tadalafil caused a significant decrease in the boundary potential of model membranes composed of palmitoyloleoylphosphatidylcholine or its mixture with cholesterol, by 70–80 mV. The reduction in the membrane dipole potential induced by inhibitors led to a 20–25% increase in the conductance of cation-selective pores formed by the antimicrobial peptide gramicidin A. The addition of sildenafil or vardenafil also led to a significant decrease in the temperature of the main phase transition of dipalmytoylphosphatidylcholine, by about 1.5 °C, while tadalafil did not change the melting temperature. Sildenafil, vardenafil, and tadalafil enhanced the pore-forming activity of the antifungal polyene antibiotic nystatin by 11, 13, and 2 times, respectively. This fact might indicate the induction of membrane curvature stress by the inhibitors. The data obtained might be of special interest for the development of lipid-mediated forms of drugs.

Enhanced performance of high‐temperature proton exchange membrane by introducing 1,2, 4‐triazole‐ functionalized graphene oxide into polybenzimidazole

1,2,4-triazole is successfully grafted onto C═C bonds of graphene oxide surface with retained carboxylic acid, hydroxy, and epoxy groups. The structure of the resulting 1,2,4-triazole-doped graphene oxide (NGO) is proved by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy spectra. The polybenzimidazole (PBI)/NGO composite membranes (NGO content:0.5%, 1%, 3%, 5%) were also prepared and subjected to the absorption of various suitable amounts of phosphoric acid (PA). As expected, the composite membranes well maintained their superior mechanical properties (57-69 MPa) containing 2 PA molecules per PBI unit. The morphological characterization using the atomic force microscopy phase images and transmission electron microscopy analysis revealed a micro-phase separation, providing continuous ionic channels and ultimately enhancing the ionic conductivity. As a result, the maximum proton conductivity of 27 mS cm−1 is achieved for PBI/NGO-3 membrane (NGO content: 3%) at 160°C under anhydrous conditions, and the maximum power density of the cell using PBI/NGO-3 membrane is 254 mW cm−2. These composite membranes displayed great potential for high-temperature proton exchange membranes under anhydrous conditions. The scanning electron microscopy images further showed the condensed structures with the suitable quantity of NGO in the composite membranes due to the hydrogen bonding and acid–base interactions between NGO and PBI. This condensed structure improved the mechanical properties, enhanced thermal stability, and increased oxidative stability of the composite membranes. Additionally, the PBI/NGO/PA composite membranes exhibit high thermal decomposition temperature (Td[5%] higher than 284°C) and superior tensile strengths (greater than 55 MPa). Remarkably, the membranes demonstrated exceptional oxidative stability and could maintain less than 15% quantity loss for more than 200 hours in Fenton's reagent (3 wt% H2O2, 4 ppm Fe2+). Novelty statement The manuscript entitled “Enhanced Performance of High-Temperature Proton Exchange Membrane by Introducing 1,2,4-Triazole Functionalized Graphene Oxide into Polybenzimidazole” was written by Haiqiu Zhang In this work, 1,2,4-triazole is successfully grafted onto graphene oxide nanosheets by C═C bonds without damaging other groups, and condensed structure improved the oxidative stability effectively, meanwhile, with the low-acid-loaded quantity and gained higher proton conductivity under anhydrous condition.

Studying the characteristics and energy performance of a composite hollow membrane for air dehumidification

Vacuum-based membrane dehumidification (VMD) unit is an energy-efficient alternative to the conventional mechanical vapor compression air-conditioning technology. Since the latent component of the cooling load can be independently handled by the VMD unit, the energy cost for cooling is substantially reduced. In this work, we investigate the dehumidification potential of a hollow membrane for VMD application. The hollow membrane offers higher dehumidification density and is more compact when compared to the flat-sheet types, thereby leading to a smaller air-handling unit (AHU) requirement. The developed hollow membrane is constructed from a polyetherimide (PEI) substrate and coated with PVA/LiCl active layers. Its apparent water vapor permeance and selectivity are 3395 gas permeation units (GPU) and 4240, respectively. During the lab-scale experimental study of a 3 m2 hollow membrane with varying air flowrates spanning 3 to 36 m3/h, it is observed that the attainable percentage of moisture removal of the membrane module is up to 86%, and the maximum dehumidification COP is 1.9. In contrast to a flat-sheet membrane module with a similar effective membrane area, the hollow membrane module is just half the size but displays the same dehumidification performance.

CO2 Abatement in the Steel Industry through Carbon Recycle and Electrification by Means of Advanced Polymer Membranes.

The potential of advanced polymer or hybrid polymer membranes to reduce CO2 emissions in steel production was evaluated. For this, a conceptual process design and assessment was performed for a process that is a combination of carbon recycling and electrification of the steel making process. The results indicate a CO2 avoidance of 9%. CO2 emissions were reduced by factor 1.78 when using renewable electricity according to the proposed scheme compared to feeding this renewable electricity to the electrical grid. The CO2 abatement potential of the studied concept is highly dependent on the CO2 conversion in the plasma torch. If CO2 conversion in the plasma torch could be increased from 84.4% to 95.0%, the overall CO2 avoidance could be further increased to 16.5%, which is comparable to the values reported for the top gas recycling blast furnace. In this case, the CO2 emissions reduction achieved when using renewable electricity in the proposed scheme compared to using the same electricity in the electrical grid increases a factor from 1.78 to 3.27.