Quaternary Ammonium Functional Groups Research Articles

Transition Metal Chalcogenides/Nonconjugated Polymer Artificial Photosystems for Photoredox Catalysis.

Surface charge transfer doping (SCTD) has been established as an efficient strategy to achieve strong electronic coupling interactions between semiconductors and dopants, which lead to highly efficient electron transport over semiconductors. Herein, we report a facile, easily accessible, and effective SCTD strategy to exquisitely modulate the interfacial charge transfer over transition metal chalcogenides (TMCs: CdS, Zn0.5Cd0.5S, CdIn2S4, and ZnIn2S4) through surface modification with a nonconjugated polymer, poly(dimethyldiallylammonium chloride) (PDDA). We provide evidence that PDDA, as a surface electron transfer acceptor, can be used to enable rapid, directional, and tunable charge transfer along with an optimal charge lifetime over TMCs in photoredox catalysis because of the high-efficiency electron-trapping property of quaternary ammonium functional groups in the molecular structure of PDDA. The thus-assembled PDDA-encapsulated TMC composite artificial photosystems demonstrate significantly enhanced and versatile photoredox catalytic activities toward visible-light-responsive photocatalytic reduction of aromatic nitro compounds, photocatalytic oxidation of aromatic alcohols, and photocatalytic H2 production, wherein the ultrathin PDDA layer accelerates the interfacial charge transport and separation rate over TMC substrates. Moreover, it was evidenced that such an interface engineering strategy is general for a collection of TMCs. Our work will provide conceptual insights into nonconjugated polymer-based artificial photosystems for optimizing solar energy utilization.

Adsorption behaviors and mechanisms of gold recovery from thiosulfate solution by ion exchange resin

The adsorption behaviors and mechanisms of gold from thiosulfate solution on strong-base anion exchange resin were systematically investigated. The comparison experiment of adsorption ability and selectivity for gold showed that gel Amberlite IRA-400 resin with Type I quaternary ammonium functional group had better adsorption performance. The increases of resin dosage, ammonia concentration and solution pH were favorable to gold adsorption, whereas the rises of cupric and thiosulfate concentrations were disadvantageous to gold loading. Microscopic characterization results indicated that gold was adsorbed in the form of [Au(S2O3)2]3– complex anion by exchanging with the counter ion Cl– in the functional group of the resin. Density functional theory calculation result manifested that gold adsorption was mainly depended on the hydrogen bond and van der Waals force generated between O atom in [Au(S2O3)2]3– and H atom in the quaternary ammonium functional group of the resin.

Impact of functionalized titanium oxide on anion exchange membranes derived from chemically modified PET bottles

The accessibility of newly affordable materials has drawn significant attention to the anion exchange membrane (AEM) technology. However, developing a high-performance AEM with excellent hydroxide conductivity and long-term durability is still challenging. The present work aims to improve the overall properties of AEMs synthesized by chemical modification of Polyethylene terephthalate (PET) bottles as the starting material. The modified PET structure was confirmed using IR, NMR, and HPLC-ESIMS analyses. AEMs were developed by incorporating quaternary ammonium (QA) functional groups into the modified PET structure, necessary for transporting anionic species (OH−). In addition, TiO2 nanoparticles grafted with silane coupling agents containing amine functional groups were synthesized via the sol-gel method and embedded in the polymer matrix. Then, the prepared nanocomposite membranes were thoroughly characterized, and the results displayed an overall improvement in the membrane's physicochemical properties. The composite membrane with 3wt% content of nanoparticle (NC3 %/M-PETm) showed remarkable conductivity, reaching 126 mS/cm at 80 °C, doubling the value of pristine membranes (64 mS/cm) while also displaying alkaline stability, retaining up to 92.2 % of conductivity after 20 days in harsh 2 M KOH at 80 °C. These results proved the suitability of these membranes for electrochemical energy applications. This innovative approach offers potential cost savings in preparing the new membranes while aligning with sustainable and circular economy principles.

Quaternized Graphene for High-Performance Moisture Swing Direct Air Capture of CO2.

Nowadays, moisture-swing adsorption technology still relies on quaternary ammonium resins with limited CO2 capacity under ambient air conditions. In this work, a groundbreaking moisture-driven sorbent is developed starting from commercial graphene flakes and using glycidyltrimethylammonium chloride for incorporation of CO2-sensitive quaternary ammonium functional groups. Boasting an outstanding CO2 capture performance under ultra-diluted conditions (namely, 3.24mmolg-1 at CO2 400ppm and 20% RH), the functionalized sorbent (fGO) features clear competitive advantages over current technologies for direct air capture. Notably, fGO demonstrated unprecedented moisture-swing capacity, ease of regenerability, versatility, selectivity, and longevity. These distinctive features position the fGO as an advanced and promising solution, showcasing its potential to outperform existing methods for moisture-swing direct air capture of CO2.

Zwitterionic functional layer modified electrospun polyurethane nanofiber membrane incorporating silver nanoparticles for enhanced antibacterial applications

Nanofiber materials, with their porous nature and high specific surface area, can effectively adsorb and capture bacteria. Additionally, their antibacterial properties can be enhanced by incorporating substances with antibacterial effects and by surface modification with special chemical functional groups. Therefore, this study uses the electrospinning method to prepare polyurethane (PU) nanofiber antimicrobial membranes. Silver nanoparticles (AgNPs) will be incorporated into the PU nanofiber membranes through a green reduction method, followed by atmospheric plasma treatment to graft the zwitterionic material (2-methacryloyloxyethyl phosphorylcholine, MPC) with quaternary ammonium functional groups onto the surface. This process will result in the production of PMPC@PU/AgNPs nanofiber antimicrobial membranes. The results show that MPC grafted onto the surface of PU/AgNPs nanofiber membranes exhibits better antibacterial capability against Escherichia coli than the pristine PU/AgNPs nanofiber antimicrobial membranes, with an antibacterial efficiency reaching 99.68 ± 0.07 %. This is attributed to the synergistic effect provided by the combination of AgNPs within the PU nanofibers and the surface grafting of zwitterionic materials, leading to an antibacterial effectiveness close to 100 %. Therefore, the prepared PMPC@PU/AgNPs nanofiber antimicrobial membrane demonstrates the potential for applications in public health, specifically in areas such as food packaging materials, membrane filters and the biomedical field.

Triphosgene crosslinked lignin-based loose nanofiltration membrane with high dye/salt separation performance, anti-fouling, and bactericidal property

Abstract A high-performance lignin-based loose nanofiltration membrane is fabricated using quaternized lignin as a novel raw material and triphosgene as a crosslinker. It has high pure water permeance (33.8 L m−2 h−1 bar−1), dye rejections, and low salt rejections during the separation of dye/salt mixtures. The quaternary ammonium functional groups endow the membrane with excellent antibacterial properties. It also has satisfactory dye-fouling resistance and separation-performance stability. Triphosgene plays an important role in optimizing the membrane structure and enhancing permeability.

Investigation on the interlayer intercalation inhibition mechanism of polyamines with different adsorption functional groups on montmorillonite: Experiment and density functional theory simulation

Water-based drilling fluids (WBDFs) are gaining popularity as they exhibit comparable inhibitory properties to oil-based drilling fluids, making them an ideal choice for drilling horizontal shale gas wells. This study focuses on understanding the intercalation inhibition mechanism of various inhibitors, namely 1,6-hexane diamine (HDA), N,N′-dimethyl-1,6-hexane diamine (DHDA), N,N,N′,N′-tetramethyl-1,6-hexane diamine (THDA), and hexamethyl diammonium chloride (HDC), each possessing different functional groups. The interaction and performance of these inhibitors on the swelling of montmorillonite (Mt) were investigated through a combination of experimental techniques containing X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, and density functional theory simulation. Results reveal that at a low dosage of 0.7 CEC (cation exchange capacity), the wet Mt-HAD, Mt-DHDA, Mt-THDA, and Mt-HDC compounds exhibit basal spacing of 1.30 nm, 1.33 nm, 1.34 nm, and 1.42 nm, respectively. The basal spacing remains unchanged when a higher dosage of 3.0 CEC is added. Comparatively, the basal spacing of dry Mt-inhibitor compounds is slightly reduced. This suggests that the addition of a smaller amount of inhibitor also demonstrates excellent inhibitory performance. Thermogravimetric and differential thermogravimetric analysis of Mt-inhibitor hybrid structure indicate that Mt-HDA compounds exhibit both low and high-temperature peaks, while Mt-DHDA, Mt-THDA, and Mt-HDC compounds only show a low-temperature peak. This indicates that while HDA partially inhibits surface hydration of Mt, DHDA, THDA, and HDC effectively inhibits surface hydration of Mt. Additionally, the microscopic mechanism of inhibitor adsorption on the Mt was explored using density functional theory simulation. HDC adsorption energy on Mt significantly increased relative to DHDA, THDA, and HDA. This indicates that inhibitors featuring quaternary ammonium functional groups exhibited superior inhibitory performance. As a result, inhibitors with quaternary ammonium functional groups hold promise as potential shale inhibitors for WBDFs.

Elimination of free fatty acid from palm oil by adsorption process using a strong base anion exchange resin

Deacidification is one of the important processes to obtain a suitable raw feedstock for the production of bio-transformer oil. This work proposed an alternative process for reducing the acidity of refined palm oil by adsorption of the free fatty acids (FFAs) using anion exchange resins (AER). The effect of the types of functional groups (tertiary amine and quaternary ammonium group) and the resin structure (gel and macroporous structure) of the commercially available resins were characterized and investigated for their adsorption ability. The adsorption kinetic and experimental conditions such as adsorption time, the moisture content in resin, and resin amount were studied. The gel-type strong-base anion exchange resins exhibited the best performance for the FFAs removal. This result suggests that the quaternary ammonium functional groups in the resin have a high dissociation capacity for anion exchange and the gel-type resins easily access by the FFAs molecules. The effect of types of functional groups is stronger than that of the resin structure. The adsorption mechanism mainly occurred via an ion exchange equilibrium rather than the hydrogen bond complex. The FFAs adsorption on the resins conformed to the pseudo-second-order kinetic model. Under optimum conditions (room temperature, atmospheric pressure, resin dosage of 0.4 wt%, and 8 h adsorption time), the Pall Tec PTA304 resin reduced the acidity in palm oil from 0.5 to 0.02 mg KOH/g with the adsorption capacity at the equilibrium of 589.5 mg/g, achieving approximately 95 % FFAs removal. The negative values of ΔGads0 and ΔHads0 demonstrated that the FFAs adsorption on the Pall Tec PTA304 resin was a spontaneous and exothermic process. This study provides an insight into the interactions between FFAs and anion exchange resins that is useful for further development of palm based bio-transformer oil.

Is It Possible to Prepare a "Super" Anion-Exchange Membrane by a Polypyrrole-Based Modification?

In spite of wide variety of commercial ion-exchange membranes, their characteristics, in particular, electrical conductivity and counterion permselectivity, are unsatisfactory for some applications, such as electrolyte solution concentration. This study is aimed at obtaining an anion-exchange membrane (AEM) of high performance in concentrated solutions. An AEM is prepared with a polypyrrole (PPy)-based modification of a heterogeneous AEM with quaternary ammonium functional groups. Concentration dependences of the conductivity, diffusion permeability and Cl− transport number in NaCl solutions are measured and simulated using a new version of the microheterogeneous model. The model describes changes in membrane swelling with increasing concentration and the effect of these changes on the transport characteristics. It is assumed that PPy occupies macro- and mesopores of the host membrane where it replaces non-selective electroneutral solution. Increasing conductivity and selectivity are explained by the presence of positively charged PPy groups. It is found that the conductivity of a freshly prepared membrane reaches 20 mS/cm and the chloride transport number > 0.99 in 4 M NaCl. A choice of input parameters allows quantitative agreement between the experimental and simulation results. However, PPy has shown itself to be an unstable material. This article discusses what parameters a membrane can have to show such exceptional characteristics.

Chemically Folded Polyelectrolytes with Superior Alkaline Stability

In recent years, the development of anion-exchange membranes (AEMs) for anion-exchange membrane fuel cell (AEMFC) applications has been rapidly growing due to their numerous advantages over mainstream proton-exchange membrane fuel cells. However, a major challenge in the development of practical AEMs is the low chemical stability of the AEM quaternary ammonium (QA) functional groups in the strongly alkaline and the relatively dry environment produced during operation of the AEMFC. Herein, we investigate the effect of polymer chain folding on the chemical stability of the QA groups. While these polymers have virtually the same chemical composition, their molecular architectures are quite different, significantly affecting the kinetics of nucleophilic attacks on the QAs embedded inside the folded chains. The stability tests reveal a remarkable improvement in the stability of the folded chains compared to the linear (unfolded) control, resulting in polyelectrolytes that are two orders of magnitude more stable. We provide here a simple method for the preparation of chemically stable AEMs with different QA groups and polymer backbones. These folded architectures present a very promising family of polyelectrolyte membranes for AEMFCs and other electrochemical applications.

Synthesis of cationic carbon quantum dot-based dual emission fluorescence sensor for detecting perrhenate anions in aqueous solutions

This study developed a carbon quantum dot to selectively detect perrhenate anions, which was used as a surrogate for the radioactive pertechnetate anion, in aqueous solutions. A blue emission carbon dot (B-CD) was prepared using a simple microwave technique, whereas a dual-emission carbon dot (D-CD) was prepared using 1,3,6-trinitropyrene. When the concentration of the perrhenate anion was increased, both B-CD and D-CD exhibited a decrease in fluorescence brightness owing to the inner filter effect; however, no changes were observed in terms of color. Therefore, cationic D-CDs (C-CDs) were synthesized by introducing quaternary ammonium functional groups on the surface of D-CD to enhance the binding characteristics with the perrhenate anion. At an excitation wavelength of 350 nm, both B-CD and D-CD failed to exhibit a decrease in fluorescence brightness; however, the change in color and reduced brightness of fluorescence were observed in C-CD because of the perrhenate anion. The change in fluorescence color can be attributed to the difference in the intensity reduction in dual-emission wavelength regions. Furthermore, C-CD exhibited linear correlations for perrhenate anion concentrations of up to 1 mM, and the limits of detection were 87 and 208 μM at excitation wavelengths of 254 and 350 nm, respectively. Additionally, the results indicate that C-CD can be used as a sensor to detect perrhenate anions despite the presence of excess chloride anions. This fluorescence change can be attributed to the photoinduced electron transfer mechanism caused by the electrostatic interactions between the cationic surface functional groups of C-CD and perrhenate anions.

Gamma Radiation Induced Degradation and Leaching Behavior of Ion Exchange Resin

Objectives : The objectives of this study were to investigate gamma radiation induced degradation and leaching behavior of nuclide and/or organic complexing agent adsorbed ion exchange resin.Methods : Cation exchange resin (IRN 77) and anion exchange resin (IRN 78) widely used in nuclear power plants were purchased. Cobalt ion and EDTA were used to represent nuclide and organic complexing agent adsorbed to ion exchange resins. Cation and anion exchange resin adsorbed cobalt ion and/or EDTA were radiated by 60Co nuclide. The radiation dose rate was 10 kGy/hr and total doses were 0, 300, 500, and 700 kGy.Results and Discussion : The sulfone and quaternary ammonium functional groups of gamma radiated ion exchange resin were degraded, indicating nuclide/organic complexing agent would be leached from ion exchange resin. It was shown that degradation of anion exchange resin was worse than that of cation exchange resin. While the high concentrations of cobalt ion and organic matter were observed in leachate from anion exchange resin, those in leachate from cation exchange resin were very low. For mixed cation and anion exchange resin, the leaching behavior of mixed resin was improved. This shows that disposal in the form of a mixed ion exchange resin was evaluated as a safer method than that of a cation or anion exchange resin alone.Conclusion : The adsorbed nuclide and organic complexing agent were leached from ion exchange resin by gamma irradiation. The leaching behavior of cation and anion exchange resin was improved by using mixed ion exchange resin.

Adsorption behavior and mechanism of amine/quaternary ammonium lignin on tungsten

Amine/quaternary ammonium lignin for adsorption of tungsten was synthesized by amination and quaternization from lignin. The adsorbent was characterized by SEM-EDS and FTIR. The effects of pH, initial concentration of tungsten, adsorption time and dosage of adsorbent on the adsorption effect were investigated. The adsorption mechanism was revealed by SEM-EDS and FTIR and XPS. The results showed that amine/quaternary ammonium lignin was loose and rough and contained a large number of phenolic hydroxyl and amine and quaternary ammonium functional groups. Using the optimum conditions, which included the pH of 4.0 and initial tungsten concentration of 800 mg·L−1 and adsorption time of 960 min, the saturated adsorption capacity of 1 g·L−1 amine/quaternary ammonium lignin for tungsten reached 421.68 mg·g−1. The adsorption followed Langmuir model and quasi-second-order kinetic model, indicating that the adsorption was monolayer homogeneous chemisorption. When the total concentration of tungsten was 0.005 mol·L−1 and the value of pH was smaller than 4.7, H2W12O406− was the existing form of tungsten and was adsorbed by electrostatic attraction of hydrogen bond and coordination with amino and ion exchange with Cl−.

The Novel Polymethacrylate Based Hydrophilic Stationary Phase for Ion Chromatography.

Ion chromatography is widely used as a useful and powerful tool for the analysis of anionic and cationic components found in waters and aqueous media. The performance and selectivity of ion chromatography are based on the stationary phase column packed material. In this study, it is aimed to develop new column material with quaternary ammonium functional group based on monodisperse polymeric particles for ion chromatography and to investigate their chromatographic performance. For the analysis of inorganic anions by ion chromatography, new stationary phases macroporous monodisperse particles based on 3-chloro-2-hydroxy propylmethacrylate-co-ethylene dimethacrylate are obtained as column packing material. 3-chloro-2-hydroxy propylmethacrylate and ethylene glycol dimethacrylate are transformed to porous monodisperse particle form by using glycidyl methacrylate as the seed latex and ethyl benzene as the porogen solvent via micro-suspension polymerization technique. Then macroporous monodisperse particles surface is functionalized by triethylamine so strong anion exchange is obtained for ion chromatography packing material. A series of stationary phases prepared from polymer particles containing different amounts of porogen solvent were tested. The results show that column packing material is successful to separate inorganic anions mixture such as F-, Cl-, NO2-, Br-, NO3- by using the carbonate and bicarbonate solutions as mobile phases.

Retention of inorganic anions using mesoporous zirconia spheres modified with anion-exchange groups as the stationary phase for ion chromatography.

A zirconia (ZrO2) stationary phase with a chemically fixed silane coupling agent (trimethyl [3-(trimethoxysilyl)propyl]ammonium chloride; TMA), which possesses quaternary ammonium functional groups, is evaluated as a separation column for ion chromatography (IC) of anions. The selectivity for anions varies depending on the amount of TMA immobilized on the ZrO2. The TMA-ZrO2, with an anion-exchange capacity of 17 ± 3µeq/g, shows an anion-exchange reaction that involves the specific retention of fluoride ion on ZrO2. The TMA-ZrO2 exhibits a decrease of the anion resolution with an increase of the eluent pH and an enhancement of the selective separation of fluorideion with an increase of the column temperature. Through this study, the TMA-ZrO2 stationary phase shows potential as a new medium for ion separation.

Enhanced removal of per- and polyfluoroalkyl substances in complex matrices by polyDADMAC-coated regenerable granular activated carbon

Granular activated carbon (GAC) has been used to remove per- and polyfluoroalkyl substances (PFASs) from industrial or AFFF-impacted waters, but its effectiveness can be low because adsorption of short-chained PFASs is ineffective and its sites are exhausted rapidly by co-contaminants. To increase adsorption of anionic PFASs on GAC by electrostatic attractions, we modified GAC's surface with the cationic polymer poly diallyldimethylammonium chloride (polyDADMAC) and tested its capacity in complex water matrices containing dissolved salts and humic acid. Amending with concentrations of polyDADMAC as low as 0.00025% enhanced GAC's adsorption capacity for PFASs, even in the presence of competing ions. This suggests that electrostatic interactions with polyDADMAC's quaternary ammonium functional groups helped bind organic and inorganic ions as well as the headgroup of short-chain PFASs, allowing more overall PFAS removal by GAC. Evaluating the effect of polymer dose is important because excessive addition can block pores and reduce overall PFAS removal rather than increase it. To decrease the waste associated with this adsorption strategy by making the adsorbent viable for more than one saturation cycle, a regeneration method is proposed which uses low-power ultrasound to enhance the desorption of PFASs from the polyDADMAC-GAC with minimum disruption to the adsorbent's structure. Re-modification with the polymer after sonication resulted in a negligible decrease in the sorbent's capacity over four saturation rounds. These results support consideration of polyDADMAC-modified GAC as an effective regenerable adsorbent for ex-situ concentration step of both short and long-chain PFASs from real waters with high concentrations of competing ions and low PFAS loads.

Use of a new zwitterionic cellulose derivative for removal of crystal violet and orange II from aqueous solutions

This study describes the synthesis of a new bioadsorbent with zwitterionic characteristics and its successful application for removal of a cationic dye (crystal violet, CV) and an anionic dye (orange II, OII) from single component aqueous systems. The new bi-functionalized cellulose derivative (MC3) was produced by chemical modification of cellulose with succinic anhydride and choline chloride to introduce carboxylic and quaternary ammonium functional groups on the cellulose surface. MC3 was characterized by several wet chemical and spectroscopic methods. The effects of solution pH, contact time, and initial solute concentration on removal of CV and OII by MC3 were investigated. Studies of the desorption and re-adsorption of the dyes were also carried out. The isotherms for adsorption of CV and OII on MC3 were satisfactorily fitted using the Konda and Langmuir models. MC3 showed experimental maximum adsorption capacities of 2403 mg g-1 for CV and 201 mg g-1 for OII. The desorption and re-adsorption results showed that MC3 could be reused in successive adsorption cycles, which is essential for minimizing process costs and waste generation. The findings showed that MC3 is a versatile biosorbent capable of efficiently removing both cationic and anionic dyes.

Quaternary functionalized mesoporous adsorbents for ultra-high kinetics of CO2 capture from air

Obstacles to widespread deployments of direct air capture of CO2 (DAC) lie in high material and energy costs. By grafting quaternary ammonium (QA) functional group to mesoporous polymers with high surface area, a unique DAC adsorbent with moisture swing adsorption (MSA) ability and ultra-high kinetics was developed in this work. Functionalization is designed for efficient delivery of QA group through mesopores to active substitution sites. This achieved ultra-high kinetics adsorbent with half time of 2.9 min under atmospheric environment, is the highest kinetics value reported among DAC adsorbents. A cyclic adsorption capacity of 0.26 mmol g−1 is obtained during MSA process. Through adsorption thermodynamics, it is revealed that adsorbent with uniform cylindrical pore structure has higher functional group efficiency and CO2 capacity. Pore structure can also tune the MSA ability of adsorbent through capillary condensation of water inside its mesopores. The successful functionalization of mesoporous polymers with superb CO2 adsorption kinetics opens the door to facilitate DAC adsorbents for large-scale carbon capture deployments.

Anion exchange chromatography – Mass spectrometry for monitoring multiple quality attributes of erythropoietin biopharmaceuticals

Assessment of critical quality attributes of the biopharmaceutical erythropoietin (EPO) prior to product release requires the use of several analytical methods. We developed an MS-compatible anion exchange (AEX) method for monitoring multiple quality attributes of EPO biopharmaceuticals. AEX was performed using a stationary phase with quaternary ammonium functional groups and a pH gradient for elution. Baseline separation of charge variants and high-quality MS data were achieved using 30 mM ammonium formate pH 5.5 and 30 mM formic acid pH 2.5 as mobile phases. In a single experiment, assessment of critical quality attributes, such as charge heterogeneity, sialic acid content and number of N-acetyllactosamine units, was possible while providing additional information on other modifications such as O-acetylation and deamidation. In addition, good repeatability and robustness for the relative areas of the individual glycoforms and average number of Neu5Ac per EPO molecule were observed. The results were comparable to common pharmacopeia and standard methods with the advantage of requiring fewer analytical methods and less sample treatment saving time and costs.

Influence of quaternization and polymer blending modification on the mechanical stability, ionic conductivity and fuel barrier of sodium alginate-based membranes for passive DEFCs

In this present study, new Quaternized sodium alginate/polyvinyl alcohol membranes (designed as QSA/PVA) has prepared using a simple solution casting method. The introduction of quaternary ammonium functional groups grafted to SA biopolymer effectively improves ionic conductivity and fuel barrier. Besides, the SA-based membranes blended with PVA and glutaraldehyde as cross-linking agent enhanced the mechanical stability of membranes. Three-dimensional network formation between QSA, PVA and GA reduced the ethanol permeability of 1.75 10−7 cm2 s−1 and increased the ionic conductivity by 2.21 × 10−2 S cm−1 at 30 °C. The water uptake, swelling ratio, tensile strength and elongation at break results of the QSA/PVA membranes shown the mechanical stability improvement of the SA-based membranes. Finally, the maximum power density of crosslinked QSA/PVA blend membrane is higher compared to pure SA membrane via passive direct ethanol fuel cells (DEFCs). Hence, crosslinked QSA/PVA blend membrane promising the potential as polymer electrolyte membranes in passive DEFCs.