Blend Membranes Research Articles

Hexagonal boron nitride-doped carbon membrane as anode for the enhanced adsorption and electrochemical oxidation of phenol

An activated carbon membrane (ACM) doped with hexagonal boron nitride (h-BN) was fabricated by using activated carbon as the raw material and phenolic resin as the binder. The preparation process involves blending raw materials, ball milling, membrane pressing, and high-temperature carbonization. The conductive ACM was employed as an anode to constitute an electrochemical membrane reactor (EMR) for phenol removal. The effect of h-BN doping rate (0–5 wt%) on the properties of ACM was explored. Results showed that ACM1 (1 wt% h-BN) displayed a small pore size (20 nm), high porosity (41.6 %), large specific surface area (446.8 m2/g), and strong mechanical strength (15.4 MPa) compared to the pristine ACM0. The oxygen precipitation potential of ACM1 (2.11 V) was much higher than that of ACM0 (1.53 V), thus reducing oxygen generation at the anode in EMR for phenol degradation. The phenol removal rate of phenol obtained from EMR with ACM1 as the anode at 1.5 V was up to 95.6 %, which was much higher than that for ACM0 (39.3 %). Density functional theory (DFT) calculations and experimental results confirmed that h-BN-doping enhanced the adsorption active sites, and adsorption energy, leading to the high performance of EMR for phenol removal. In addition, the equilibrium adsorption capacity of ACM1 (10.2 mg/g) was much higher than that of ACM0 (3.7 mg/g). The C atoms adjacent to pyridine N in ACM1 were identified as the adsorption and active catalytic sites by X-ray photoelectron spectroscopy (XPS) and DFT calculations. Therefore, this study sheds light on the design and fabrication of conductive carbon membranes for enhanced performance in industrial wastewater treatment.

Preparation of modified atmosphere packaging based on the respiratory characteristics of cherry tomato and its freshness preservation application

Cherry tomato (Lycopersicon esculentum Mill.) belongs to the respiratory leap type of fruit, post-harvest respiratory metabolism exuberant, easy to lead to nutrient loss, tissue destruction, and then rotting and deterioration, seriously affecting its commercial value. Therefore, research on post-harvest preservation technology of cherry tomatoes is crucial for related industries. Spontaneous modified atmosphere film packaging technology can extend the storage period of fruits and vegetables by adjusting the gas concentration of the storage environment, so that the fruits and vegetables can be maintained at a level suitable for their storage. In this study, the respiration model of cherry tomatoes at different temperatures was established by measuring the respiration rate of cherry tomatoes at different temperatures. It was found that the respiration rate of cherry tomatoes increased with increasing temperature and gradually decreased with increasing storage time. T-test results showed that there was no significant difference between the experimental values and the predicted values. The chemical kinetic model and its equilibrium equation were used to determine the parameters of modified atmosphere packaging of cherry tomatoes. PEG/PVDF membranes and SPEEK/PEG/PVDF blend membranes were prepared with sulfonated polyether ether ketone (SPEEK), polyvinylidene fluoride (PVDF) and polyethylene glycol (PEG) according to the parameters of modified atmosphere membranes to keep cherry tomatoes fresh. The results showed that there was a significant effect of package method on the preservation parameters of cherry tomatoes, the SPEEK/PEG/PVDF membrane treatment group significantly reduced the weight loss rate of cherry tomatoes and maintained the lower film permeability and higher sound fruit rate, hardness, titratable acid (TA) content, VC content and total soluble solids (TSS) content of cherry tomatoes. It can effectively delay the ripening and senescence of cherry tomatoes and extend the fruit storage period.

Development and Study of Novel Ultrafiltration Membranes Based on Cellulose Acetate.

Recently, increasing attention of researchers in the field of membrane technology has been paid to the development of membranes based on biopolymers. One of the well-proven polymers for the development of porous membranes is cellulose acetate (CA). This paper is devoted to the study of the influence of different parameters on ultrafiltration CA membrane formation and their transport properties, such as the variation in coagulation bath temperature, membrane shrinkage (post-treatment at 80 °C), introduction to casting CA solution of polymers (polyethylene glycol (PEG), polysulfone (PS), and Pluronic F127 (PL)) and carbon nanoparticles (SWCNTs, MWCNTs, GO, and C60). The structural and physicochemical properties of developed membranes were studied by scanning electron and atomic force microscopies, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle measurements. The transport properties of developed CA-based membranes were evaluated in ultrafiltration of bovine serum albumin (BSA), dextran 110 and PVP K-90. All developed membranes rejected 90% compounds with a molecular weight from ~270,000 g/mol. It was shown that the combination of modifications (addition of PEG, PS, PL, PS-PL, and 0.5 wt% C60) led to an increase in the fluxes and BSA rejection coefficients with slight decrease in the flux recovery ratio. These changes were due to an increased macrovoid number, formation of a more open porous structure and/or thinner top selective, and decreased surface roughness and hydrophobization during C60 modification of blend membranes. Optimal transport properties were found for CA-PEG+C60 (the highest water-394 L/(m2h) and BSA-212 L/(m2h) fluxes) and CA-PS+C60 (maximal rejection coefficient of BSA-59%) membranes.

Development of microfiltration membranes based on polysulfone and polyetherimide blends.

In this study, membranes blended with polysulfone (PSU) and polyetherimide (PEI) polymers in different ratios were fabricated. Their potential to remove pollutants from rivers, which are a potential drinking water source, was investigated. Scanning electron microscopy analysis revealed that the PSU membranes had a dense and homogeneous layer, whereas the addition of PEI formed a spongy substrate. The water content of the fabricated membranes varied between 5.37 and 22.42%, porosities 28.73-89.36%, contact angles 69.18-85.81%, and average pure water fluxes 257.25-375.32 L/m2 h. The blended membranes removed turbidity, chloride, alkalinity, conductivity, sulfate, iron, manganese, and total organic carbon up to 98.32, 92.28, 96.87, 90.67, 99.58, 94.63, 97.48, and 79.11%, respectively. These results show that when PEI was added to the PSU polymer, the filtration efficiency increased owing to an increase in the hydrophilicity of the membranes. Blending these two polymers enabled the optimization of membrane properties such as permeability, selectivity, and mechanical strength. In addition, membrane fabrication processes are simple and incur low costs.

Preparation and Characterization of SPEEK–PVA Blend Membrane Additives with Colloidal Silica for Proton Exchange Membrane Fuel Cell

An inexpensive membrane with high proton conductivity and high fuel cell performance, which can be an alternative to Nafion for PEMFC (Proton exchange membrane fuel cell), will overcome the obstacle to widespread commercialization of fuel cells due to high cost. For this purpose, SPEEK (sulfonated polyether ether ketone)-PVA (polyvinyl alcohol) blend membranes with colloidal silica additives were synthesized in this study. Ludox AS-40 was used as the colloidal silica source and the blend membrane was prepared by solution casting method. Water uptake capacity, swelling property, size change, dynamic mechanical analysis, ion exchange capacity, AC impedance analysis, hydrolytic and oxidative stability experiments of the synthesized Ludox additives blend membranes for fuel cell application were carried out, and the membranes were also characterized by FTIR (Fourier transform infrared) analysis. While the water uptake capacities of SPEEK/PVA membranes containing 1% Ludox, 5% Ludox, and 10% Ludox at room temperature were found to be 14.08%, 14.84%, and 16.6%, respectively, the water uptake capacities at 80oC increased to 14.73%, 15.17%, and 17.11%. The proton conductivities of 1% Ludox, 5% Ludox and 10% Ludox doped SPEEK/PVA membranes at 80oC were 0.25 S/cm, 0.56 S/cm, and 0.65 S/cm, respectively. Similarly, ion exchange capacities were determined to be 1.41 meq/g, 1.63 meq/g, and 1.71 meq/g, respectively. All Ludox-added membranes exhibited excellent hydrolytic stability, retaining approximately 88% of their mass after 650 h. In addition, in oxidative stability experiments carried out in 4 ppm Fe+ 2 at 80oC, the 10% Ludox-added membrane exhibited the highest weight loss of 88.8% at the end of 24 h, while the 5% Ludox-additive membrane retained 91.6% of its total weight. Considering the proton conductivity and longevity tests of the synthesized membranes, they are thought to be promising structures.Graphical

High performance and antifouling zeolite@polyethersulfone/cellulose acetate asymmetric membrane for efficient separation of oily wastewater

Microfiltration membranes have emerged as a promising alternative for oily wastewater treatment due to their high efficiency, low cost, and ease of operation. In this study, polyethersulfone (PES), cellulose acetate (CA), and 4A zeolite were blended to fabricate asymmetric membranes by the phase inversion technique and examined in oily wastewater treatment. Kerosene was chosen as a model polluting oil. The fabricated pure PES membrane (P), PES membranes incorporating 4A zeolite (ZP), PES membrane blended with CA (PC), and PES/CA blended membranes with 4A zeolite (ZPC) were characterized using field emission scanning electron microscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, porosity, and contact angle to study the structure properties of these membranes. The performance of membranes was examined by water permeation, oil permeation flux, oil rejection, flux recovery ratio, and relative flux reduction. The ZPC membranes showed the highest performance in comparison with other prepared membranes. Incorporating 4A zeolite nanoparticles with 0.5 wt% into the PES/CA blended membrane significantly enhanced the microfiltration performance and decreased the contact angle of the P membrane from 70° to 29.8°. The effect of operation parameters such as transmembrane pressure (1–4 bar), feed temperature (25–50 ºC), and concentration of oil feed solution (250–1000 mg/L) on the permeation flux and oil rejection was studied on the PES/CA blended membrane containing 0.5 wt% 4A zeolite (0.5%ZPC). The 0.5%ZPC membrane showed improved porosity of 87.7% and it gave the highest value of pure water flux of 91.1 L/m2.h, oil permeation flux of 75.55 L/m2.h, maximum oil rejection of 98.8%, flux recovery ratio of 97.7%, and relative flux reduction of 21.8%. The permeation flux given by the 0.5%ZPC membrane was improved by about 8 times that of the P membrane. Re-usability studies verified the durability of the blended membranes and their performance in oily wastewater treatment.

Study of Thermal Behavior and Activation Energy of Various Polymer Nanocomposite Blend Membranes

Study of Thermal Behavior and Activation Energy of Various Polymer Nanocomposite Blend Membranes

In-situ generation of anti-fouling TpPa/PVDF membranes showing excellent photocatalytic degradation and self-cleaning for dyes in water

Covalent organic frameworks (COFs) have been widely studied in membrane separation technology due to their high porosity, high specific surface area, and tunable pore size. However, COF particles tend to aggregate in blend membranes. In this study, in-situ generation of 2,4,6-Triformylphloroglucinol p-Phenylenediamine (TpPa) was carried out in Polyvinylidene fluoride/N,N-dimethylacetamide (PVDF/DMAc), followed by nonsolvent-induced phase separation (NIPS) method to obtain TpPa/PVDF membranes. The introduction of hydrophilic TpPa resulted in improved hydrophilicity and increased roughness of the membrane. During the filtration of dyes including Methylene Blue, Congo Red, and Eriochrome Black T, the TpPa/PVDF membrane exhibited high rejection rates (>90 %) and improved permeation flux (6–8 times of the original PVDF membrane). Investigation of its photocatalytic ability revealed that the TpPa/PVDF membrane exhibited excellent photocatalytic degradation of dyes, making it suitable for self-cleaning of fouled membranes and allowing for multiple reuse (up to 8 times). In the 6-cycle filtrations of Bovine Serum Albumin (BSA) and Humic Acid (HA), the membrane showed not only high rejection and permeation but also superior flux recovery rate (FRR), indicating good anti-fouling ability. This study has achieved efficient treatment of dye wastewater through membrane separation technology and has provided a novel anti-fouling COFs-modified membrane with photocatalytic self-cleaning ability.

One-Step Prepared Multifunctional Polyacrylonitrile/MIL-100(Fe) Membrane with High-Density Porous Fibers for Efficient Dye/Oil Wastewater Remediation.

With environmental pollution becoming more serious, developing efficient treatment technologies for all kinds of organic wastewater has become the focus of current research. In this work, the coaxial electrospinning technology was used to one-step fabricate a porous and underwater superoleophobic polyacrylonitrile nanofibrous membrane with an Fe-based metal-organic framework (MIL-100(Fe)). Benefiting from the synergistic effect of two jets, the nanofibers are smaller and denser, which prompt the exposure of more nanomaterial additives (MIL-100(Fe)). The BET surface area increased to 202.888 m2/g, and the membranes demonstrated outstanding underwater superoleophobicity. Moreover, compared with traditional blended matrix membranes by the single-axis method, separation of the modifier and membrane matrix material by coaxial methods also maintained excellent mechanical properties, which enhanced Young's modulus 3.4 times (∼1.34 MPa). As a result, facing soluble dyes, the porous C-PAN/MIL-100(Fe) membrane can demonstrate outstanding and fast adsorptive property (the Qm of MB and CR reached 44.71 and 88.74 mg g-1, respectively). For oily emulsion, the hydrophilic and oleophobic nanofibrous reticular surface provided excellent separation performance (flux: 1124.0-1549.3 L m-2 h-1, R > 98%). Moreover, the porous and underwater superoleophobic C-PAN/MIL-100(Fe)-0.5 membrane can synchronously purify the dye/oil mixture emulsions by one-step filtration. Based on the above performance, we believe that the modified nanofibrous membrane prepared by one-step coaxial electrospinning technology can promote more studies of the development of membrane preparation technology in the field of oily wastewater treatment.

Pervaporation Separation of Tetrahydrofuran/Water Azeotropic Mixtures using Phosphorylated Blend Membranes

In this study, we developed novel phosphoric acid crosslinked blend membranes for the pervaporation separation of tetrahydrofu-ran/water mixtures. Sodium alginate and chitosan blend membranes were prepared by solution casting and solvent evaporation technique. These blend membranes were crosslinked with phosphoric acid in isopropanol/water baths and used for pervaporation separation of feed mixtures ranging from 6 to 43 wt.% water in tetrahydrofuran (THF)/water mixtures at 30 °C. Crosslinking was confirmed by Fourier transform infrared (FTIR) and Ion Exchange Capacity (IEC) study. Thermal stability and crystallinity of the membranes were determined from thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies respectively. The surface morphology of the membranes was observed using Scanning electron microscopy (SEM). Sorption studies were carried out to evaluate the extent of interaction and degree of swelling of the membranes in THF, water and binary mixtures. The effect of experimental parameters such as feed composition, membrane thickness, and permeate pressure on separation performance of the phosphorylated membranes were determined. These membranes were found to have good potential for breaking the azeotrope of 94 wt.% THF with a selectivity of 459 and normalized flux of 0.25 kg m−2 h−1 10 µm. The membrane performance exhibited a reduction in selectivity and an improvement in flux with increasing feed water compositions. Selectivity improved and flux decreased with increasing membrane thickness. Both flux and selectivity decreased with increasing permeate pressure.

Ultra-Thin Ion Exchange Membranes by Low Ionomer Blending for Energy Harvesting.

Exploring the utilization of ion exchange membranes (IEMs) in salinity gradient energy harvesting, a technique that capitalizes on the salinity difference between seawater and freshwater to generate electricity, this study focuses on optimizing PVDF to Nafion ratios to create ultra-thin membranes. Specifically, our investigation aligns with applications such as reverse electrodialysis (RED), where IEMs facilitate selective ion transport across salinity gradients. We demonstrate that membranes with reduced Nafion content, particularly the 50:50 PVDF:Nafion blend, retain high permselectivity comparable to those with higher Nafion content. This challenges traditional understandings of membrane design, highlighting a balance between thinness and durability for energy efficiency. Voltage-current analyses reveal that, despite lower conductivity, the 50:50 blend shows superior short-circuit current density under salinity gradient conditions. This is attributed to effective ion diffusion facilitated by the blend's unique microstructure. These findings suggest that blended membranes are not only cost-effective but also exhibit enhanced performance for energy harvesting, making them promising candidates for sustainable energy solutions. Furthermore, these findings will pave the way for advances in membrane technology, offering new insights into the design and application of ion exchange membranes in renewable energy.

Ultrafiltration polyanionic poly (3‐sulfopropyl methacrylate) membranes with enhanced antifouling and water flux

AbstractPolyethersulfone (PES) membranes are prevalent in the field of water treatment owing to their exceptional separation efficiency, robust mechanical properties, and resistance to chemical degradation. Nevertheless, these membranes are prone to fouling, resulting in a decrease in both flux and ultrafiltration efficiency. In the present study, PES membranes are blended with poly (3‐Sulfopropyl Methacrylate) (PSPMA) in various weight percentages (0%–3%) to improve their antifouling and ultrafiltration properties. The physicochemical properties of the blended membranes, including surface morphology, contact angle, hydrophilicity and surface energy are evaluated. The findings indicate that incorporation PSPMA results in an enhancement of the hydrophilic properties and surface charge of the PES membranes, assessed by employing Bovine Serum Albumin (BSA) as a representative protein. Modified blended membranes display greater Flux Recovery Ratio (FRR%) and exhibit superior fouling resistance. Under the same experimental conditions (0.2 MPa applied pressure), a pure water flux of 154.18 L·m−2·h−1 for PES/PSPMA membrane found substantially greater than pure PES membrane (103.52 L·m−2·h−1) along with Total Fouling Ratio (TFR) of 36% and 64.9% respectively. Exceptional antimicrobial efficacy for modified membranes is revealed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) using disc diffusion technique rendering them well‐suited for water treatment applications.

Surface characterization and Remazol Red adsorption by asymmetric polyethersulfone membranes modified by polyelectrolyte complexes

AbstractPolyethersulfone (PES) membranes containing 4‐fluorophenyl sulfone‐terminated poly(diallylpiperidinium hexafluorophosphate)‐sulfonated poly(ethylene terephthalate) polyelectrolyte complexes (PECs) were obtained via phase inversion using three different methods that enabled the complexation of polyelectrolytes (PELs) to occur before, after, and during membrane formation. Atomic force microscopy‐infrared spectroscopy analysis revealed varying concentrations of the polyanion depending on the preparation method and confirmed the presence of PECs in the membranes, highlighting an increase in surface roughness. Zeta potential measurements demonstrated positive surface charges for the membrane comprising PES and the polycation. The reduction in zeta potential in PEC membranes corresponded with the neutralization of positive groups by sulfonated poly(ethylene terephthalate. Scanning electron microscopy micrographs depicted surface imperfections in PEC membranes, emphasizing the influence of PECs on membrane surfaces. The water contact angle decreased, indicating increased hydrophilicity in PEC membranes. Additionally, dye adsorption results showcased significant adsorption, with the membranes absorbing at least 60% of Remazol Red from an aqueous solution. Notably, the Blend membrane outperformed others, exhibiting an exceptional adsorption rate exceeding 92%.

Cellulose Acetate-Ionic Liquid Blends as Potential Polymers for Efficient CO2 Separation Membranes.

CO2 capture, applied in CO2 separation from natural gas or in CO2/N2 separation from power plant flue gas streams, is of great importance for technical, economic, and environmental reasons. The latter seems important because CO2, as a greenhouse gas, is considered the main contributor to global warming. Using polymeric membranes for CO2 separation presents several advantages, such as low energy demand, small equipment volume, and the absence of liquid waste. In this study, two ionic liquids (ILs) were used for the preparation of cellulose acetate (CA)-IL blend membranes for potential CO2 capture applications, namely, 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim+][HSO4-]) and choline glycine ([Ch+]Gly-), as they present adequate CO2 dissolution ability. The first IL is commercially available, whereas the latter was synthesized by a novel route. Several composite membranes were prepared through the solvent casting technique and characterized by a variety of methods, including thermogravimetry, calorimetry, FTIR spectroscopy, and X-ray diffraction. The CO2 sorption in the composite membranes was experimentally measured using the mass loss analysis (MLA) technique. The results showed that the ILs strongly interacted with the C=O groups of CA, which exhibited high affinity with CO2. In the case of [Bmim+][HSO4-], a reduction in the available sites that allow strong intermolecular interactions with CO2 resulted in a decrease in CO2 sorption compared to that of pure CA. In the case of [Ch+]Gly-, the reduction was balanced out by the presence of specific groups in the IL, which presented high affinity with CO2. Thus, the CA-[Ch+]Gly- blend membranes exhibited increased CO2 sorption capability, in addition to other advantages such as non-toxicity and low cost.

Surface Bioengineering of Mo2Ga2C MAX Phase to Develop Blended Loose Nanofiltration Membranes for Textile Wastewater Treatment.

The potential of blended loose nanofiltration membranes (LNMs) to fractionate dyes and inorganic salts in textile wastewater has become a focus of attention in recent years. In this research work, we fabricated LNMs based on polysulfone (PSf) membranes blended with l-histidine amino acid-functionalized Mo2Ga2C MAX phase (His-MAX). Scanning electron microscopy (SEM), atomic force microscopy (AFM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), contact angle, ζ-potential, porosity, and pore size analyses were employed to characterize the LNMs. Blending 0.75 wt % of His-MAX additive with the PSf tailored the LNM's features by making it more water-friendly, increasing its porosity, enlarging its pores, and making its surface smoother. The pure water flux of 127.6 L/m2 h was achieved by LNM containing 0.75 wt % His-MAX, which was 2.5 times greater than the bare one. The mentioned LNM displayed a flux recovery ratio (FRR) of 68.27 and 98.57, 98.31, and 99.7% rejections for Direct red 23, Acid brown 75, and Reactive blue 21 solutions (100 mg/L), respectively. The 0.75 wt % His-MAX LNM could reject 99.1% of dye and 11.5% of salt while maintaining an FRR of 91.19% after four cycles of filtering a binary mixture solution containing Reactive blue 21 and Na2SO4. These findings highlight the potential of the fabricated LNM for desalinating dye solutions.

In-situ ionized construction of PVDF/sodium polyacrylate-grafted-PVDF blend ultrafiltration membrane with stable anti-oil-fouling ability for efficient oil-in-water emulsion separation

Traditional polymeric membranes usually suffer from serious oil fouling and quick decline of water flux when separating oil-in-water emulsions. In this work, we report the fabrication of the sodium polyacrylate (PAAS) blended polyvinylidene fluoride (PVDF) ultrafiltration membrane which behaves hydrophilicity, underwater low-oil-adhesive superoleophobicity and outstanding anti-oil-fouling ability even for viscous crude oil. The blend membrane was fabricated via a two-step method, including the nonsolvent-induced phase inversion of PVDF/polyacrylic acid-grafted-PVDF (PVDF/PAA-g-PVDF) blend membrane and the subsequent in-situ ionization of PAA into PAAS. The two-step method improves the affinity between the strong hydrophilic additive PAAS and the hydrophobic polymer matrix PVDF, thus endowing the blend membrane with long-term stable superwetting property for 1,100 days. The PVDF/PAAS-g-PVDF blend membrane can efficiently separate multiple emulsifier-stabilized oil-in-water emulsions with ultrahigh separation efficiency of 99.97% (the residual oil content in the filtrate is lower than 3 ppm after one-step separation) and high water flux of 350 L m-2 h-1 bar-1. The blend membrane also shows good cycling performance, and can be easily cleaned by water washing during several separation cycles of the crude oil-in-water emulsion. This work inspires a feasible route of fabricating stable anti-oil-fouling membranes for separation of emulsified oily water.

Controlled drug release from the polycaprolactone-gelatin blend membranes for cancer therapy and microbial strains growth inhibition

Controlled drug release from the polycaprolactone-gelatin blend membranes for cancer therapy and microbial strains growth inhibition

Novel Fluoroboric Acid Additive for Blend Membrane to be Used in PEM Fuel Cell, Characterization Studies, and Performance Test

This study focuses on developing an alternative membrane for PEMFC due to the disadvantages of using Nafion. Fluoroboric acid (FBA) was used as an additive material to SPEEK-PVA blend membranes at different weight ratios (1%, 5%, 7.5%, 10%, and 12.5%), and a synthesis procedure was carried out with the solution-casting. Thermal crosslinking was performed with all membranes. Utilizing FBA, with its highly electronegative fluorine groups, is a novel approach expected to enhance proton conductivity. The structural, morphological, and thermal properties of the synthesized membranes were determined by FTIR, XRD, SEM, TGA-DTG, and DSC. Water uptake capacity (WUC), swelling property, area change, dynamic mechanical analysis, ion exchange capacity (IEC), AC impedance analysis, hydrolytic stability, and oxidative stability analyses were performed for fuel cell applications. Although FBA does not have a crystal structure, the synergy it created with the SPEEK-PVA membrane increased the crystallinity of the membrane and, accordingly, glass transition temperature. SEM images of membranes at a ratio above 7.5% show that agglomerations occur in the structure and this is supported by other analyses. It was determined that the membrane composition with the highest WUC (16.44%), IEC (1.55 meq/g), and proton conductivity (0.57 S/cm) values contained 7.5% FBA from the characterization studies, and a single-cell performance test was actualized with this. 418 mA/cm2 current density and 250.8 mW/cm2 power density were obtained at 0.6 V cell potential, with the membrane containing 7.5% FBA. This study shows that the synthesized membrane, especially the FBA, is a promising option for PEMFC application.Graphical

Preparation of polydimethylsiloxane/poly (styrene-butadiene-styrene) blend membrane by in-situ reactive compatibilizer γ-methacryloxy propyl trimethoxyl silane for efficient recovery of n-butanol from aqueous solution

For commercial use, separating membranes need to have outstanding chemical, thermal, and mechanical stability. Moreover, striking a compromise between selectivity and permeability is essential for commercialization. Motivated by the robust and extensible properties of plant cell walls， we develop a strategy to build a cavity cell structure on the surface of the polydimethylsiloxane (PDMS) membrane utilizing a styrene-butadiene-styrene block copolymer (SBS) phase as the “cell wall" to enhance mechanical properties and prevent water permeation to achieve high selectivity. To obtain a controlled split-phase structure, γ-methacryloxy propyl trimethoxyl silane (WD-70) was selected for in situ accommodation of PDMS and SBS. The best results were achieved during the pervaporation separation of 1 wt % n-butanol aqueous solution at 70 °C, with 67.86 μm•kg/(m2•h) flux and an ultra-high separation factor of 73.6, as well as long-term operating stability. All the raw ingredients are affordable and readily available. The synergistic effect of PDMS and SBS mitigated the trade-off effect of the polymer membrane and improved the separation performance.

An exploration of novel natural gas leak detection based on the efficient CH4/N2 separation of polymer blend membrane

The CH4/N2 high-efficiency membrane separation technology is capable of effectively enriching CH4 from natural gas, and holds great potential for application in the fields of biogas purification and natural gas pipeline leak detection. However, preparing high-performance separation membranes is challenging due to the similarity between CH4 and N2 molecules. To enhance the CH4/N2 separation performance, block polyetheramide copolymer (Pebax)/EVA blended membranes were fabricated in this study. Additionally, a novel gas leakage detection tube was prepared. The EVA14 (14 wt% VA) membrane exhibits an optimal transport-facilitated channel among a series of pure EVA membranes, resulting in a CH4 permeability of 21.41 Barrer and CH4/N2 selectivity reaches 1.80 under mixed-gas feed conditions at 35 °C. The CH4 permeability of Pebax/EVA (30 wt%) reaches 120.5 Barrer by physical blending, and the CH4 permeability is increased by 191 % in comparison with pure EVA14 membrane. The Pebax/EVA (10 wt%) membrane exhibits the optimum CH4/N2 selectivity, and compared with pure EVA membrane increased by 35.5 %. EVA and Pebax polymers are blended for the first time for CH4/N2 separation, and the blending of block polyetheramide copolymer intensifies the membrane's separation performance comprehensively. The natural gas leak detection tube was fabricated with a membrane, offering a new and efficient CH4/N2 separation strategy.