Sulfonated Poly Ether Ether Ketone Research Articles

Microbial fuel cell for oilfield produced water treatment and reuse: Modelling and process optimization

Oilfield produced water is one of the vast amounts of wastewater that pollute the environment and cause serious problems. In this study, the produced water was treated in a microbial fuel cell (MFC), and response surface methodology and central composite design (RSM/CCD) were used as powerful tools to optimize the process. The results of two separate parameters of sulfonated poly ether ether ketone (SPEEK) as well as nanocomposite composition (CNT/Pt) on the chemical oxygen demand (COD) removal and power generation were discussed. The nanocomposite was analyzed using XRD, SEM, and TEM. Moreover, the degree of sulfonation (DS) was measured by NMR. A quadratic model was utilized to forecast the removal of COD and power generation under distinct circumstances. To obtain the maximum COD removal along with maximum power generation, favorable conditions were achieved by statistical and mathematical techniques. The findings proved that MFC could remove 92% of COD and generate 545 mW/m2 of power density at optimum conditions of DS=80; and CNT/Pt of 14 wt% CNT- 86 wt% Pt.

Dual-functional coordination polymers with high proton conduction behaviour and good luminescence properties.

Two coordination polymers, [M(5-hip)(H2O)3]n (M = Cd2+ (1), Zn2+ (2), 5-hip = 5-hydroxyisophthalic acid), have been synthesized under hydrothermal conditions. The crystal structure reveals that complexes 1 and 2 have 1D chain structures by the coordination of metal ions and 5-hip. 1D chains are connected by hydrogen bonds to form a 3D structure. AC impedance analysis shows that the proton conductivity of complexes 1 and 2 comes up to 1.58 × 10-3 S cm-1 (98%RH, 343 K) and 5.27 × 10-4 S cm-1 (98%RH, 353 K), respectively. To further improve the proton conductivity, a hybrid membrane was prepared by the solution casting method with complexes as fillers and sulfonated polyether ether ketone (SPEEK) as the organic matrix. The proton conductivity of hybrid membranes 1@SPEEK-5 and 2@SPEEK-5 is 1.97 and 1.58 times higher than that of pure SPEEK membranes, respectively. Furthermore, the two complexes are excellent fluorescent sensors, which could detect Cr2O72- in aqueous solution with high sensitivity and selectivity. Both of them have low detection limits for Cr2O72- in aqueous solution, where the detection limit of complex 1 is 0.8 μM and that of complex 2 is 1 μM. The above work demonstrates that the two complexes are dual-functional materials with high proton conduction and good fluorescence properties.

Nanocomposite membrane by incorporating graphene oxide in sulfonated polyether ether ketone for direct methanol fuel cell

Few-layers graphene oxide enriched with oxygen functional groups is successfully obtained and incorporated into sulfonated polyether ether ketone (SPEEK) matrix. The functional groups and the surface modification of membranes were identified using FTIR spectroscopy, and X-ray Photoelectron Spectroscopy (XPS). Subsequently, FESEM was employed to study the surface morphology changes, and the X-Ray diffraction (XRD) was performed to ascertain the crystallinity of the fabricated membrane. The distribution of carbonaceous fillers GO in SPEEK matrix was found to actively improved the ion exchange capacity (IEC), and concurrently obstructed the methanol crossover, thus making them intriguing candidates as proton exchange membranes (PEMs).

MXene potassium titanate nanowire/sulfonated polyether ether ketone (SPEEK) hybrid composite proton exchange membrane for photocatalytic water splitting.

A cross-linked sulfonated polyether ether ketone (C-SPEEK) was incorporated with MXene/potassium titanate nanowire (MKT-NW) as a filler and applied as a proton exchange membrane for photocatalytic water splitting. The prepared hybrid composite PEM had proton conductivity of 0.0097 S cm−1 at room temperature with an ion exchange capacity of 1.88 meq g−1. The hybrid composite proton exchange membrane is a reactive membrane which was able to generate hydrogen gas under UV light irradiation. The efficiency of hydrogen gas production was 0.185066 μmol within 5 h for 12% wt of MKT-NW loading. The results indicated that the MKT-NW/C-SPEEK membrane is a promising candidate for ion exchange with hydrogen gas evolution in photocatalytic water splitting and could be applied as a renewable source of energy to use in various fields of applications.

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

AbstractIn this research, the preparation of low cost proton exchange membranes (PEMs) based on sulfonated poly ether ether ketone (SPEEK) for application in the microbial fuel cells (MFCs) is studied. Sulfonated polystyrene (SPS) and phosphotungstic acid (PWA) were employed to improve the performance of PEM through the creation of more proton pathways. At first, the sulfonation of PEEK and polystyrene were performed through two modified methods to obtain uniform and high degree of sulfonation (DS) of the polymers and then, the PEMs were prepared through the solution casting method. Accordingly, the formation of uniform skin layer was confirmed by the SEM micrographs. Blending the aforementioned additives to the SPEEK polymer solution significantly enhanced the proton conductivity, water uptake and durability of the modified membranes. The proton conductivities of SPEEK/SPS and SPEEK/PWA membranes at additive/SPEEK weight ratio of 0.15 were 45.3% and 26.2% higher than that of the commercial Nafion117 membrane, respectively. Moreover, the degradation times for the abovementioned modified membranes were 140 and 350 min which indicated satisfactory oxidation stability. Besides, the aforementioned membranes exhibited two times more water uptake compared to the neat SPEEK membrane. Finally, SPEEK/SPS and SPEEK/PWA membranes produced 68% and 36% higher maximum power in the MFC, compared to the commercial Nafion117 membrane. Therefore, the fabricated PEMs are potentially suitable alternatives to be used in the fuel cell applications.

Influence of surface-modified glass fibers on interfacial properties of GF/PEEK composites using molecular dynamics

In this paper, molecular dynamics (MD) simulations are carried out to explore the influence of surface modification of glass fiber on interfacial binding energy and failure behavior of GF/PEEK composites. The silane coupling agent and sulfonated PEEK (SPEEK) are employed to modify the surface of glass fibers (GF), and the results reveal that the SPEEK can be employed as an adhesive sizing agent to improve the interfacial bonding strength of GF/PEEK composites. In addition, the synergistic mechanism of non-bonding and mechanical interlocking is investigated by using MD simulations. The interface shear simulation results demonstrate that the interfacial shear strength of composite increased and more resin molecules are found on the surface after SPEEK is incorporated into the GF surface. Moreover, compared with surface-untreated short GF-reinforced PEEK composite, the experimental results demonstrate that the tensile and bending strength of SGF/PEEK composite are improved after interface modification with SPEEK by 21.4% and 30.2%, respectively. The current study presents the utilization of MD simulation for interface design to enhance the mechanical properties of fiber-reinforced PEEK composites.

Dual-Functional Phosphorene Nanocomposite Membranes for the Treatment of Perfluorinated Water: An Investigation of Perfluorooctanoic Acid Removal via Filtration Combined with Ultraviolet Irradiation or Oxygenation.

Nanomaterials with tunable properties show promise because of their size-dependent electronic structure and controllable physical properties. The purpose of this research was to develop and validate environmentally safe nanomaterial-based approach for treatment of drinking water including removal and degradation of per- and polyfluorinated chemicals (PFAS). PFAS are surfactant chemicals with broad uses that are now recognized as contaminants with a significant risk to human health. They are commonly used in household and industrial products. They are extremely persistent in the environment because they possess both hydrophobic fluorine-saturated carbon chains and hydrophilic functional groups, along with being oleophobic. Traditional drinking water treatment technologies are usually ineffective for the removal of PFAS from contaminated waters, because they are normally present in exiguous concentrations and have unique properties that make them persistent. Therefore, there is a critical need for safe and efficient remediation methods for PFAS, particularly in drinking water. The proposed novel approach has also a potential application for decreasing PFAS background levels in analytical systems. In this study, nanocomposite membranes composed of sulfonated poly ether ether ketone (SPEEK) and two-dimensional phosphorene were fabricated, and they obtained on average 99% rejection of perfluorooctanoic acid (PFOA) alongside with a 99% removal from the PFOA that accumulated on surface of the membrane. The removal of PFOA accumulated on the membrane surface achieved 99% after the membranes were treated with ultraviolet (UV) photolysis and liquid aerobic oxidation.

Enhanced Performance of Sulfonated GO in SPEEK Proton-Exchange Membrane for Microbial Fuel-Cell Application

AbstractSulfonated graphene oxide (SGO) was prepared using sulfuric acid and used as a nanofiller at various concentrations in self-fabricated sulfonated polyetheretherketone (SPEEK) to produce nan...

Strontium ranelate incorporated 3D porous sulfonated PEEK simulating MC3T3-E1 cell differentiation.

Polyetheretherketone (PEEK) has been used as an implant material because it has similar mechanical properties to natural bone. However, inferior osseointegration and bioinertness hamper the clinical application of PEEK. In this study, the surfaces of sulfonated three-dimensional (3D) PEEK porous structures were loaded with different concentrations of strontium ranelate, a compound commonly used in the treatment or prevention of osteoporosis by promoting bone formation and inhibiting bone resorption. Field-emission scanning electron microscopy was used to characterize the topography of the structures, elemental carbon, oxygen and strontium contents were measured by X-ray photoelectron spectroscopy, and surface zeta potentials and water-contact angle were also measured. The results indicated that strontium ranelate was successfully loaded onto the 3D porous structures. In vitro cellular results showed that strontium ranelate-treated sulfonated PEEK (SP-SR) strengthened the adhesion of MC3T3-E1 cells. The activity of alkaline phosphatase, collagen secretion and extracellular matrix mineralization deposition of MC3T3-E1 cells were also improved on the surface of SP-SR. These results indicate that SP-SR could serve a new implant candidate for surgical treatment.

MXene-Based Hydrogels Endow Polyetheretherketone with Effective Osteogenicity and Combined Treatment of Osteosarcoma and Bacterial Infection.

After an osteosarcoma resection, the risks of cancer recurrence, postoperative infection, and large bone loss still threaten patients' health. Conventional treatment relies on implanting orthopedic materials to fill bone defects after surgery, but it has no ability of destroying residual tumor cells and preventing bacterial invasion. To tackle this challenge, here, we develop a novel multifunctional implant (SP@MX/GelMA) that mainly consists of MXene nanosheets, gelatin methacrylate (GelMA) hydrogels, and bioinert sulfonated polyetheretherketone (SP) with the purpose of facilitating tumor cell death, combating pathogenic bacteria, and promoting osteogenicity. Because of the synergistic photothermal effects of MXene and polydopamine (pDA), osteosarcoma cells are effectively killed on the multifunctional coatings under 808 nm near-infrared (NIR) irradiation through thermal ablation. After loading tobramycin (TOB), the SP@MX-TOB/GelMA implants display robust antibacterial properties against Gram-negative/Gram-positive bacteria. More importantly, the multifunctional implants are demonstrated to have superior cytocompatibility and osteogenesis-promoting capability in terms of cell replication, spreading, alkaline phosphatase activity, calcium matrix mineralization, and in vivo osseointegration. Accordingly, such photothermally controlled multifunctional implants not only defeat osteosarcoma cells and bacteria but also intensify osteogenicity, which hold a greatly promising countermeasure for curing postoperative tissue lesion from an osteosarcoma excision.

Highly Sulfonated Poly(Ether Ether Ketone) Blend with Hydrophobic Polyether Sulfone as an Alternative Electrolyte for Proton Exchange Membrane Fuel Cell

Highly sulfonated poly(ether ether ketone) (sPEEK) offers high proton conductivity but lacks in mechanical stability due to poor swelling degree. Therefore, a promising approach has been introduced in this study by incorporating the hydrophobic polyether sulfone (PES) into sPEEK matrix. The effect of incorporating PES at various composition contents (5, 10, 15 and 20 wt%) is investigated toward the membrane properties. The membranes are characterized in terms of structural, morphology, thermal, mechanical, physicochemical and electrochemical properties. It has been found that the incorporation of PES in the highly sulfonated PEEK has significantly improved the mechanical and thermal stability without sacrificing the swelling degree and hydrogen permeability. The sPEEK/PES-5 membrane shows the most promising performance among others exhibiting a comparable proton conductivity of 7.18 mS/cm to that of pristine highly sulfonated PEEK with 8.14 mS/cm. Meanwhile, the power density result of the sPEEK/PES-5 membrane shows 99.29 mW/cm2 at par with the commercial Nafion 117 membrane of 135.75 mW/cm2. In conclusion, the sPEEK/PES blend membrane has shown favorable physicochemical properties and considerably high performance obtained from the blended sPEEK membrane at 5 wt% of PES loading that can be considered as a promising alternative membrane for proton exchange membrane fuel cell.

Impact of SPEEK on PEEK membranes: Demixing, morphology and performance enhancement in lithium membrane extraction

Acid resistance membrane plays a key role in membrane extraction of lithium ions for ensuring performance stability, yet many are not suitable because of their high ion diffusion resistance. We report here our endeavor in further reducing the ion diffusion resistance of a novel poly (ether ether ketone, PEEK) membrane for lithium extraction from salt-lake brine. We blended PEEK with sulfonated PEEK (SPEEK) and their miscibility was researched by evaluating the mixing free energy and glass transition temperature in the whole mixing range. Using methanesulphonic acid (MSA) and sulfuric acid (SA) as the solvent and water as precipitation media, thermodynamic and kinetic behaviors in phase separation were analyzed. Cloud point of a quasi-ternary PEEK/SPEEK-MSA/SA-H2O indicated a low water tolerance; the nominal diffusion coefficient showed maximal value at 50/50% mixing ratio, indicating the quickest demixing. PEEK/SPEEK 50/50 showed the highest water permeability and lithium diffusion, extraction and stripping fluxes. Nearly five times lithium extraction flux and about two times stripping flux as compared to the PEEK membrane were obtained. Disruption of crystalline formation in PEEK by amorphous SPEEK contributed to the open morphology and reduced resistance. The results widen the scopes of membrane materials for membrane extraction of lithium and other ions.

Flexible humidity sensors for wireless monitoring based on electrospun sulfonated polyether ether ketone (SPEEK) nanofibres

The development of flexible and high-performance humidity sensors for continuous wireless monitoring is receiving increasing attention. In this work, electrospun sulfonated polyether ether ketone (SPEEK) nanofibres with different sulfonation degrees were prepared and directly deposited onto flexible substrates for humidity sensor applications. On a logarithmic scale, both resistance (Rdc) and capacitance (Cs) of the SPEEK nanofibre-based sensors showed linear responses to changes between 30 and 80 % in relative humidity (RH). Our devices showed higher sensitivities (up to LogRdc(Ω)/RH(%) = -0.06952 and LogCs(F)/RH(%) = 0.07078) and improved linearity (over 0.980) than humidity sensors using continuous SPEEK films. The humidity sensors exhibited fast sensing responses (75 s), mechanical flexibility and durability. These beneficial properties can be attributed to the fibrous structure of electrospun SPEEK. The potential of SPEEK fibre-based humidity sensor was further demonstrated by monitoring real-time humidity levels using a printed near-field communication (NFC)-enabled circuit for wireless sensing.

Additively Manufactured Polyetheretherketone (PEEK) with Carbon Nanostructure Reinforcement for Biomedical Structural Applications

This study is focused on carbon nanostructures (CNS), including both carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), reinforcement of medical‐grade polyetheretherketone (PEEK), and in vitro bioactivity for biomedical structural applications. CNS/PEEK scaffolds and bulk specimens, realized via fused filament fabrication (FFF) additive manufacturing, are assessed primarily in the low‐strain linear‐elastic regime. 3D printed PEEK nanocomposites are found to have enhanced mechanical properties in all cases while maintaining the desired degree of crystallinity in the range of 30–33%. A synergetic effect of the CNS and sulfonation toward bioactivity is observed—apatite growth in simulated body fluid increases by 57% and 77%, for CNT and GNP reinforcement, respectively, doubling the effect of sulfonation and exhibiting a fully‐grown mushroom‐like apatite morphology. Further, CNT‐ and GNP‐reinforced sulfonated PEEK recovers much of the mechanical losses in modulus and strength due to sulfonation, in one case (GNP reinforcement) increasing the yield and ultimate strengths beyond the (non‐sulfonated) printed PEEK. Additive manufacturing of PEEK with CNS reinforcement demonstrated here opens up many design opportunities for structural and biomedical applications, including personalized bioactivated surfaces for bone scaffolds, with further potential arising from the electrically conductive nanoengineered PEEK material toward smart and multifunctional structures.

Physicochemical characterization of low sulfonated polyether ether ketone/Smectite clay composite for proton exchange membrane fuel cells

AbstractPolyether ether ketone (PEEK) with a low sulfonation degree was blended using different proportions of sodium rich Smectite clay (3 and 6 wt%) to use as an electrolyte membrane for fuel cell application. The structural functionalities, surface morphologies, and the thermal stability of the resultant composite membranes were characterized using Fourier‐transform infrared spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy, atom force microscopy, and thermo‐gravimetric analysis. FT‐IR showed that no chemical reactions take place between the sulfonated polyether ether ketone (SPEEK) and the clay with different ratios. XRD diffractograms illustrated a lower degree of crystallinity of the blended SPEEK than pristine SPEEK. The elaborated composite membranes proved to have a higher thermal stability than SPEEK. Furthermore, the SPEEK/clay composite membranes with 3 and 6 wt% in clay loading had higher water uptake and lower methanol uptake than those in pristine SPEEK It was also shown that, the incorporation of sodium ions rich Smectite clay layers between the clusters in SPEEK improved the conductivity to 2 × 10−2 S/cm at 140°C (for 6 wt% in clay) without compromising the dimensional stability of the composite membranes. These results propose the composite membranes as a potential candidate for methanol fuel cells at temperatures above 120°C making SPEEK composite membrane competitive to that of Nafion membrane.

Nanohybrid Membrane Synthesis with Phosphorene Nanoparticles: A Study of the Addition, Stability and Toxicity.

Phosphorene is a promising candidate as a membrane material additive because of its inherent photocatalytic properties and electrical conductance which can help reduce fouling and improve membrane properties. The main objective of this study was to characterize structural and morphologic changes arising from the addition of phosphorene to polymeric membranes. Here, phosphorene was physically incorporated into a blend of polysulfone (PSf) and sulfonated poly ether ether ketone (SPEEK) doping solution. Protein and dye rejection studies were carried out to determine the permeability and selectivity of the membranes. Since loss of material additives during filtration processes is a challenge, the stability of phosphorene nanoparticles in different environments was also examined. Furthermore, given that phosphorene is a new material, toxicity studies with a model nematode, Caenorhabditis elegans, were carried out to provide insight into the biocompatibility and safety of phosphorene. Results showed that membranes modified with phosphorene displayed a higher protein rejection, but lower flux values. Phosphorene also led to a 70% reduction in dye fouling after filtration. Additionally, data showed that phosphorene loss was negligible within the membrane matrix irrespective of the pH environment. Phosphorene caused toxicity to nematodes in a free form, while no toxicity was observed for membrane permeates.

Effects of different sulfonation times and post-treatment methods on the characterization and cytocompatibility of sulfonated PEEK.

Polyetheretherketone (PEEK) has been becoming a popular implant material in orthopaedic applications. The lack of bioactivity affects PEEK's long-term lifetime, and appropriate surface modification is an effective way to enhance its bioactivity. Sulfonation of PEEK can endow PEEK with a 3 D porous network surface and improve its bioactivity. This study is aimed at exploring an optimal sulfonation time and a post-treatment method of PEEK sulfonation. PEEK was immersed into concentrated sulfuric acid for different sulfonation times and experienced different post-treatment methods to turn into sulfonated PEEK (SPEEK). The immersion times were 0.5 min (SPEEK0.5), 1 min (SPEEK1), 3 min (SPEEK3), 5 min (SPEEK5) and 7 min (SPEEK7), and the post-treatment methods were acetone rinsing (SPEEK-T1), hydrothermal treatment (SPEEK-T2) and NaOH immersion (SPEEK-T3). Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy, hydrophilic property, ion release and cell viability evaluations were performed to optimize the sulfonation time, and the SEM, EDS, ion release and cell viability were analysed to optimize the post-treatment method. The results showed a porous network structure was formed on all samples of SPEEK, and the porous structure became more obvious and the S concentration increased with increasing sulfonation time. However, too long of an immersion time (SPEEK7) tended to damage the superficial porous structure and left a higher content of sulfuric acid, which could inhibit the growth of MC3T3E1 cells on its surface. In addition, the surface morphology, residual sulfuric acid and cytocompatibility of SPEEK-T1, SPEEK-T2 and SPEEK-T3 were not distinctly different. In conclusion, a 5-min sulfonation time was considered to be the optimal selection, and acetone rinsing, hydrothermal treatment and NaOH immersion showed the same effect in removing the residual sulfuric acid. The understanding of optimal sulfonation time and post-treatment method can provide a theoretical basis in preparing SPEEK for orthopaedic applications.

Friedel-Crafts self-crosslinking of sulfonated poly(etheretherketone) composite proton exchange membrane doped with phosphotungstic acid and carbon-based nanomaterials for fuel cell applications

In this work, self-crosslinked sulfonated polyether etherketone membrane (C-SPEEK) was synthesized by Friedel-Crafts alkylation at 130 °C with chloromethylated sulfonated polyether etherketone (SPEEK-Cl). The water uptake (WU) of the C-SPEEK was 47.75% with a 8.69% swelling rate (SR) at 60 °C, compared with the sulfonated polyether etherketone membrane (SPEEK) with WU of 110.60% and SR of 57.99%. The contradiction between dimensional stability and proton conductivity under high sulfonation degree was overcome. The self-crosslinking composite membranes were prepared by doping with carbon nanomaterials (Graphite oxide, GO; reduced graphene oxide, rGO and carbon nanotubes, CNTs) and phosphotungstic acid (HPW). Since HPW and carbon nanomaterials incorporated in membrane facilitate protons conduction via both Grotthuss and Vehicle mechanisms, the hybrid membranes demonstrated the improved conductivities. At 80 °C, C-SPEEK/HPW/GO showed proton conductivity as high as 119.04 mS/cm, which was 2.4 folds higher than that of the C-SPEEK. Furthermore, the superior performance of C-SPEEK/HPW/GO was further validated through H2/O2 single cell test. The C-SPEEK/HPW/GO produced a higher power output of 876.80 mW/cm2, whereas only 776.72 mW/cm2 for C-SPEEK was recorded. Thus, C-SPEEK/HPW/GO and C-SPEEK may be promising membrane materials for potential applications in fuel cells.

Modelling IR Spectra of Sulfonated Polyether Ether Ketone (SPEEK) Membranes for Fuel Cells

SPEEK (sulfonated polyether ether ketone) membranes have been prepared and characterized. The SPEEK membrane geometry and theoretical vibration spectra calculated using density functional theory (DFT) as depending from membrane chain length and polymer cross-linking. Analyzed the limitations of the method by comparing theoretical and experimental IR spectra.

ELECTROSPUN STRONTIUM CROSS-LINKED SULFONATED POLY (ETHER ETHER KETONE) SPEEK NANOFIBER FOR PROTON EXCHANGE MEMBRANE FUEL CELL

Strontium (Sr) cross-linked nanofibrous membranes of sulfonated polyether ether ketone (SPEEK) were successfully prepared using the electrospinning technique. Metal-polymer physical cross-linked has been proposed as a way to improve the mechanical and chemical stabilities of the electrospun SPEEK membrane which we found in this finding can help to reduced water uptake compared with the non-crosslinked membrane. Physical cross-linked of Sr-SPEEK membranes were fabricated by immersion process which were than electrospun into nanofibrous membranes. The morphologies of electrospun Sr-SPEEK membrane, fabricated under different concentrations of Sr were presented which show up to 6% concentration of Strontium was able to be electrospun. On the electrical properties of the electrospun membrane, conductivity for the sample with 6% Sr weight percentage has given 0.188 S/cm which is about 80% higher than the film cast Nafion-117 at 80˚C as cited before. This particular result is a hallmark of the studies as it shows that a combination of nanostructured with crosslink is proven to work in favor of producing proton exchange membrane fuel cell (PEMFC) which performed much better than Nafion based membrane.