SPES Matrix Research Articles

Tailoring ultrafiltration membranes with chemically modified human hair waste for improved permeability and antifouling performance

Human hair, a pervasive waste product, has the potential to pose environmental challenges due to its widespread accumulation. Therefore, exploring of alternatives that repurpose this waste into a valuable raw material aligns with the principles of the circular economy. This study introduces a novel protocol for crafting biohybrid ultrafiltration (UF) membranes with tailored charges, enhanced hydrophilicity, and notable attributes of high flux, rejection rate, and resistance to fouling. These membranes have been engineered by combining sulfonated poly(ethersulfone) (SPES) with chemically modified human hair (HH) filler, referred to as HH-SO3-NH2, utilizing the non-solvent induced phase separation (NIPS) approach. The preparation of HH-SO3-NH2 involved converting of oxidized thiol groups within human hair to sulfonic acid. Subsequently, 1 and 3 wt percent of HH-SO3-NH2 were integrated into the SPES matrix to formulate the biohybrid membranes. After incorporating HH-SO3-NH2, the biohybrid membranes changed in mechanical properties, porosity, and surface morphology, resulting in increased hydrophilicity. The pure water flux exhibited a systematic rise with higher HH-SO3-NH2 content-specifically, the hybrid membrane with 3 wt% HH-SO3-NH2 achieved a water flux of 239 L m−2 h−1 at 1 bar feed pressure, representing a 1.5-fold increase compared to the bare membrane's 175 L m−2 h−1 flux. The anti-fouling performance was assessed using humic acid (HA) and the hybrid membranes demonstrated removal efficiency of HA exceeding 99% without compromising rejection rates.

Sulphonated poly(ethersulfone)/carbon nano-onions-based nanocomposite membranes with high ion-conducting channels for salt removal via electrodialysis.

Herein, we are reporting the carbon nano onions (CNO)-based sulphonated poly(ethersulfone) (SPES) composite membranes by varying CNO content in SPES matrix for water desalination applications. CNOs were cost-effectively synthesized using flaxseed oil as a carbon source in an energy efficient flame pyrolysis process. The physico- and electrochemical properties of nanocomposite membranes were evaluated and compared to pristine SPES. Moreover, the chemical characterisation of composite membranes and CNOs were illustrated using techniques such as nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA) and universal tensile machine (UTM). In the series of nanocomposite membranes, SPES-0.25 composite membrane displayed the highest water uptake (WU), ion exchange membrane (IEC) and ionic conductivity (IC) values that were enhanced by 9.25%, ~ 44.78% and ~ 6.10%, respectively, compared to pristine SPES membrane. The electrodialytic performance can be achieved maximum when membranes possess low power consumption (PC) and high energy efficiency (Ee). Therefore, the value of Ee and Pc for SPES-0.25 membrane has been determined to be 99.01 ± 0.97% and 0.92 ± 0.01 kWh kg-1, which are 1.12 and 1.11 times higher than the pristine SPES membrane. Hence, integrating CNO nanoparticles into the SPES matrix enhanced the ion-conducting channels.

ZIF-67 Incorporated Sulfonated Poly (Aryl Ether Sulfone) Mixed Matrix Membranes for Pervaporation Separation of Methanol/Methyl Tert-Butyl Ether Mixture.

Mixed matrix membranes (MMMs) with nano-fillers dispersed in polymer matrix have been proposed as alternative pervaporation membrane materials. They possess both promising selectivity benefiting from the fillers and economical processing capabilities of polymers. ZIF-67 was synthesized and incorporated into the sulfonated poly (aryl ether sulfone) (SPES) matrix to prepare SPES/ZIF-67 mixed matrix membranes with different ZIF-67 mass fractions. The as-prepared membranes were used for pervaporation separation of methanol/methyl tert-butyl ether mixtures. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and laser particle size analysis results show that ZIF-67 is successfully synthesized, and the particle size is mainly between 280 nm and 400 nm. The membranes were characterized by SEM, atomic force microscope (AFM), water contact angle, thermogravimetric analysis (TGA), mechanical property testing and positron annihilation technique (PAT), sorption and swelling experiments, and the pervaporation performance was also investigated. The results reveal that ZIF-67 particles disperse uniformly in the SPES matrix. The roughness and hydrophilicity are enhanced by ZIF-67 exposed on the membrane surface. The mixed matrix membrane has good thermal stability and mechanical properties, which can meet the requirements of pervaporation operation. The introduction of ZIF-67 effectively regulates the free volume parameters of the mixed matrix membrane. With increasing ZIF-67 mass fraction, the cavity radius and free volume fraction increase gradually. When the operating temperature is 40 °C, the flow rate is 50 L·h-1 and the mass fraction of methanol in feed is 15%, the mixed matrix membrane with ZIF-67 mass fraction of 20% shows the best comprehensive pervaporation performance. The total flux and separation factor reach 0.297 kg·m-2·h-1 and 2123, respectively.

Investigation of the versatility of SPES membranes customized with sulfonated molybdenum disulfide nanosheets for DMFC applications

Sulfonated poly(ether sulfone) (SPES) based proton exchange membranes (PEMs) are fabricated using sulfonated molybdenum disulfide (S-MoS2) nanosheets via facile solution casting method. SPES (DS = 30%) and S-MoS2 are synthesized and sulfonation is evidently observed in FTIR and XRD analysis. The anchoring of sulfonic acid group on exfoliated molybdenum disulfide (E-MoS2) and elemental composition of S-MoS2 are confirmed by XPS spectrum. Physico-chemical characteristics such as ion-exchange capacity (IEC), water uptake, swelling ratio and oxidation stability are found to be increases after the addition of S-MoS2 into SPES matrix. Increment in S-MoS2 content in SPES matrix decreases the surface contact angle due to the increase in hydrophilicity. Further, the dispersing ability of S-MoS2 in SPES matrix is evidently shown by an increase in surface roughness, tensile strength and thermal stability of the SPES/S-MoS2 nanocomposite membranes. On the whole, SPES/S-MoS2-1 membrane showed the highest proton conductivity of 5.98 × 10−3 Scm−1, selectivity of 19.6 × 104 Scm−3s, peak power density of 28.28 mWcm−2 and lesser methanol permeability of 3.05 × 10−8 cm2s−1. The strong interfacial interaction between SPES and S-MoS2 in nanocomposite membranes create strong hydrogen bond network to facilitate the proton conduction pathway via both vehicle and Grotthuss type mechanisms. Overall results suggested that the SPES/S-MoS2 nanocomposite membranes are superior and appropriate alternative for commercially high-cost Nafion® membranes for use in renewable direct methanol fuel cell (DMFC) devices.

Constructing Amino-Functionalized Flower-like Metal-Organic Framework Nanofibers in Sulfonated Poly(ether sulfone) Proton Exchange Membrane for Simultaneously Enhancing Interface Compatibility and Proton Conduction.

A novel flower-like MIL-53(Al)-NH2 nanofiber (MNF) was successfully constructed, in which the electro-blown spinning Al2O3 nanofibers were introduced as Al precursors to coordinate with ligand in hydrothermal reaction for the formation of MOFs nanofibers. By incorporating the functional and consecutive MNFs fillers in sulfonated poly(ether sulfone) (SPES) matrix, high-performance MNFs@SPES hybrid membranes were obtained. Specifically, the peak stress strength could be strengthened to 33.42 MPa and the proton conductivity was remarkably improved to 0.201 S cm-1 as MNFs content increased to 5 wt %, achieving a simultaneous improvement on proton conduction and membrane stability. The highly promoted performance could be ascribed to the synergy advantages of unique structure and amino modification of MNFs: (1) The flower-like nanofiber structure of MNFs with high surface area could be beneficial to construct long-range and compatible interfaces between MNFs and SPES matrix, leading to sufficient continuous proton pathways as well as strengthened stability for the hybrid membrane. (2) The hydrophilic MNFs rendered the hybrid membrane with sufficient water retention for proton transfer via Vehicle mechanism. (3) Functional -NH2 groups of MNFs and -SO3H groups of SPES were consecutively and tightly bonded via acid-base electrostatic interactions, which further accelerated the proton conduction via Grotthuss hopping mechanism and effectively suppressed the methanol penetration in the meanwhile for the MNFs@SPES hybrid membranes.

Assembly of MIL-101(Cr)-sulphonated poly(ether sulfone) membrane matrix for selective electrodialytic separation of Pb2+ from mono-/bi-valent ions

Acidic functionalized polymer-MIL-101 composite membrane were considered as a promising material for the electrodialytic separation of targeted bi-valent metal ion from industrial waste water. Architectural strategy for these specific selective membrane was based on the presence of acidic functional groups (–SO3H) and coordinately unsaturated metal sites. In general, scalability and mechanical stability were the key limitations for MOF based membranes. But we report a simple preparation of flexible and mechanical stable MIL-101(Cr) composite membrane. In this method, MIL-101 was entrapped within hydrophilic pore/ion conducting channels of the sulphonated poly(ether sulfone) (SPES) matrix by hydrophilic-hydrophilic interactions. Further, incorporation of MIL-101(Cr) within SPES matrix significantly improved the membrane’s properties. We adopted a simple approach enabling fine distribution of hydrophilic material within the pore of acidic functionalized polymer containing hydrophilic and hydrophobic segments. MIL-101 is expected to be confined responsible for the pore modification. Well optimized MIL-10 membrane showed good permselectivity for mono-valent (Na+) and bi-valent (Zn2+, and Ni2+) ions, while impervious nature for Pb2+. Further, simple preparation and cost-effective nature of SPES@MIL-101 membranes are the attractive feature for fabricating Pb2+ impervious membrane for its selective separation. Reported new class of membrane preparation protocols open a window for fabricating nano-channels for selective ion transport.

Sulfonated poly (ether sulfone) composite membranes customized with polydopamine coated molybdenum disulfide nanosheets for renewable energy devices

Sulfonated poly (ether sulfone) (SPES) membranes are fabricated using polydopamine layered molybdenum disulfide (PDM) nanosheets. The exfoliated molybdenum disulfide (E-MoS2) nanosheets are subjected to surface coating with self-polymerization of dopamine and probed by FT-IR and EDAX analysis. Membranes are characterized by FT-IR, XRD, SEM, AFM, contact angle, water uptake, ion-exchange capacity, proton conductivity, methanol permeability, TGA, mechanical and oxidative stability. Characterization results confirmed that the SPES/PDM nanocomposite membranes are better than bare SPES and Nafion-212 membranes possibly due to the interface electrostatic attraction between amine groups (-NH2 and –NH-) of PDM with sulfonate (SO3−) group of SPES which create the strong acid-base pair. This result in the enhancement of the proton transport pathway in nanocomposite membranes and also the PDM reduces the methanol transport channels by generating the tortuous path. SPES/PDM-1 membrane exhibits the highest proton conductivity of 5.64 × 10-3 Scm-1, methanol resistivity of 2.23 × 10-8 cm2s-1 and selectivity of 22 × 104 Scm-3s. SPES/PDM membranes are displayed better thermal, mechanical and oxidative stability probably due to the uniform distribution of PDM on SPES matrix as evidenced by SEM images. Overall results confirmed that the SPES/PDM membranes will be an alternate to expensive Nafion in clean energy DMFC devices.

Zn-MOF@SPES composite membranes: synthesis, characterization and its electrochemical performance

ABSTRACTHerein, the applicability of MOF-based composite ion exchange membranes have been explored. Series of membranes have been synthesized by varying Zn-MOF content in SPES matrix. Number of spectroscopic techniques were used to characterize the successful synthesis of Zn-MOF and composite membranes. Physicochemical properties of composite membranes have been evaluated and observed to be enhanced. Composite membranes have been subjected to salt removal efficiency through electrodialysis, and observed that Z-2 membrane shows best flux and salt removal efficiency than others, which were 1.72 molm−2h−1 and 1.0 kWhkg−1 respectively with superior electro-chemical performance.

Fabrication of Binary Sulfonated Poly Ether Sulfone and Sulfonated Polyvinylidene Fluoride‐Co‐Hexafluoro Propylene Blend Membrane as Efficient Electrolyte for Proton Exchange Membrane Fuel Cells

Polymer electrolyte membrane (PEM) is pivotal in proton exchange membrane fuel cells (PEMFCs) with enhanced power performances. We reported a sulfonated (poly ether sulfone) (SPES) and sulfonated polyvinylidene fluoride‐co‐hexafluoro propylene (SPVdF‐HFP) blend membrane for the PEMFC. We fabricated the SPES/SPVdF‐HFP blend membrane via a simple solvent‐casting method with 10 or 20% of SPVdF‐HFP. It exhibited enhanced proton conductivity and was assigned to the synergism between SPES and SPVdF‐HFP. FE‐SEM images of composite membrane revealed the effectual dispersion of SPVdF‐HFP in the SPES matrix, which may offer an extend networks for facile proton conduction. Moreover, integration of SPVdF‐HFP effectively increased the power density of blend membrane i.e., 262.78 mW/cm2, it was higher by 1.51 fold compared to bare SPES membrane (173.67 mW/cm2).

Enhanced Electrochemical Performance of Stable SPES/SPANI Composite Polymer Electrolyte Membranes by Enriched Ionic Nanochannels.

Herein, we present the results of sulfonated polyaniline (SPANI) and sulfonated poly(ether sulfone) (SPES) composite polymer electrolyte membranes. The membranes are established for high-temperature proton conductivity and methanol permeability to render their applicability. Composite membranes have been prepared by modifying the SPES matrix with different concentrations of SPANI (e.g., 1, 2, 5, 10, and 20 wt %). Structural and thermomechanical characterizations have been performed using the transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analyzer techniques. Physicochemical and electrochemical properties have been evaluated by water uptake, ion-exchange capacity, dimensional stability, and proton conductivity. Methanol permeability experiment was carried out to analyze the compatibility of prepared membranes toward direct methanol fuel cell application and found the lowest methanol permeability for PAS-5. Also, the membranes reveal excellent thermal, mechanical, and physicochemical properties for their application toward high-temperature electromembrane processes.

Chitin nanowhisker-supported sulfonated poly(ether sulfone) proton exchange for fuel cell applications

To balance the relationship among proton conductivity and mechanic strength of sulfonated poly(ether sulfone) (SPES) membrane, chitin nanowhisker-supported nanocomposite membranes were prepared by incorporating whiskers into SPES. The as-prepared chitin whiskers were prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) mediated oxidation of α-chitin from crab shells. The structure and properties of the composite membranes were examined as proton exchange membrane (PEM). Results showed that chitin nanowhiskers were dispersed incompactly in the SPES matrix. Thermal stability, mechanical properties, water uptake and proton conductivity of the nanocomposite films were improved from those of the pure SPES film with increasing whisker content, which ascribed to strong interactions between whiskers and between SPES molecules and chitin whiskers via hydrogen bonding. These indicated that composition of filler and matrix got good properties and whisker-supported membranes are promising materials for PEM.

PWA/silica doped sulfonated poly(ether sulfone) composite membranes for direct methanol fuel cells

A novel sulfonated poly(ether sulfone) (SPES)/phosphotungstic acid (PWA)/silica composite membranes for direct methanol fuel cells (DMFCs) application were prepared. The structure and performance of the obtained membranes were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), water uptake, proton conductivity, and methanol permeability. Compared to a pure SPES membrane, PWA and SiO2 doped membranes had a higher thermal stability and glass transition temperature (Tg) as revealed by TGA-FTIR and DSC. The morphology of the composite membranes indicated that SiO2 and PWA were uniformly distributed throughout the SPES matrix. Proper PWA and silica loadings in the composite membranes showed high proton conductivity and sufficient methanol permeability. The selectivity (the ratio of proton conductivity to methanol permeability) of the SPES-P-S 15% composite membrane was almost five times than that of Nafion 112 membrane. This excellent selectivity of SPES/PWA/silica composite membranes indicate a potential feasibility as a promising electrolyte for DMFC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Sulfonated poly(ether sulfone)/silica composite membranes for direct methanol fuel cells

AbstractA series of sulfonated poly(ether sulfone) (SPES)/silica composite membranes were prepared by sol–gel method using tetraethylorthosilicate (TEOS) hydrolysis. Physico–chemical properties of the composite membranes were characterized by thermogravimetric analysis (TGA), X‐ray diffraction (XRD), scanning electron microscope–energy dispersive X‐ray (SEM–EDX), and water uptake. Compared to a pure SPES membrane, SiO2 doping in the membranes led to a higher thermal stability and water uptake. SEM–EDX indicated that SiO2 particles were uniformly embedded throughout the SPES matrix. Proper silica loadings (below 5 wt %) in the composite membranes helped to inhibit methanol permeation. The permeability coefficient of the composite membrane with 5 wt % SiO2 was 1.06 × 10−7 cm2/s, which was lower than that of the SPES and just one tenth of that of Nafion® 112. Although proton conductivity of the composite membranes decreased with increasing silica content, the selectivity (the ratio of proton conductivity and methanol permeability) of the composite membrane with 5 wt % silica loading was higher than that of the SPES and Nafion® 112 membrane. This excellent selectivity of SPES/SiO2 composite membranes could indicate a potential feasibility as a promising electrolyte for direct methanol fuel cell. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Sulfonated poly(ether sulfone) (SPES)/boron phosphate (BPO 4) composite membranes for high-temperature proton-exchange membrane fuel cells

A new series of sulfonated poly(ether sulfone) (SPES)/boron phosphate (BPO 4) composite membranes for proton-exchange membrane fuel cells (PEMFCs) applications, with a BPO 4 content up to 40 wt%, were prepared by a sol–gel method using tripropylborate and phosphoric acid as precursors. Compared to a pure SPES membrane, BPO 4 doping in the membranes led to a higher thermal stability and glass-transition temperature ( T g) as revealed by TGA–FTIR, DSC and DMTA. Water uptake and oxidative stability were significantly increased by increasing the content of BPO 4. At both operating temperature conditions, namely 20 °C and 100 °C, the tensile strength of all the composite membranes were lower than that of the SPES membrane. However, even when the content of BPO 4 was as high as 30%, the composite membrane still possessed strength similar to the Nafion 112 membrane. SEM–EDX indicated that the BPO 4 particles were uniformly embedded throughout the SPES matrix, which may facilitate proton transport. Proton conductivities increased from 0.0065 to 0.022 S cm −1 at room temperature as BPO 4 increased from 0 to 40%. The conductivities also increased with the temperature. The SPES/BPO 4 composite membrane is a promising candidate for PEMFCs applications, especially at higher temperatures.

Effect of TiO<sub>2</sub> Nanoparticles on the Hydrophilicity of Sulfonated-Polyethersulfone

Sulfonated-polyethersulfone/TiO2 (SPES/TiO2) nanoparticle composites with different TiO2 content were prepared by a sol-gel process. These composites have nanosized TiO2 rich domains well dispersed within SPES matrix observed by SEM photograph. The effect of TiO2 nanoparticles on the hydrophilicity of SPES was discussed by contact angle goniometer. The mechanism of the hydrophilicity improvement of these composites was analyzed by the molecular interaction theory and FT-IR. The hydrogen bond and coordination bond between SPES and TiO2 nanoparticle were observed. Comparing with the pure SPES, the SPES/TiO2 composites exhibited an outstanding increase in hydrophilicity.

Preparation and Properties of Sulfonated Poly(ether sulfone)/Boron Phosphate Composite Proton Exchange Membranes

Sulfonated poly(ether sulfone)(SPES)/boron phosphate(BPO4) composite membranes for application in high temperature proton exchange membrane fuel cells(PEMFCs) were successfully prepared by the sol-gel technique.The structure and performance of the obtained membranes were characterized by thermogravimetric analysis(TGA)-Fourier transform infrared(FTIR) spectroscopy,differential scanning calorimetry(DSC),and scanning electron microscopy(SEM).Results showed that the composite membranes had higher thermal stabilities and glass transition temperatures(Tg),less swelling and excellent oxidative stability.The morphology of the composite membranes indicated that BPO4 particles were uniformly distributed throughout the SPES matrix,which may facilitate proton transport.Proton conductivities of composite membranes increased as BPO4 content increased.SPES/BPO4 composite membranes showed good proton conductivities up to and above 120 ℃.SPES/BPO4 composite membranes are promising materials for possible use in PEMFCs,especially for high-temperature applications.