Maximum Ion Exchange Capacity Research Articles

Development and analysis of the physical and electrochemical characteristics of a nano titanium (IV) tungstomolybdate supported on polyethersulfone composite cation exchange membrane

In this study, a series of novel composite membranes were synthesized utilizing polyethersulfone (PES), sulfonated polyethersulfone (SPES) as base polymer and titanium tungstomolybdate (TWM) as an inorganic ion exchange resin. The membranes were fabricated through the solution casting technique. The composite membranes exhibited enhanced thermal and chemical stability, as well as improved oxidative stability. All the composite membranes demonstrated higher hydrophilicity, with the SPES-TWM composite membranes displaying the lowest contact angle of 65°. The composite membranes also displayed favorable water uptake (up to 26% for SPES-TWM) and lower methanol uptake (maximum 12% for SPES-TWM) and better mechanical stability (maximum of 40 MPa for SPES-TWM). The SPES-TWM composite membranes exhibited the maximum ion exchange capacity of 1.32 meq.g−1. The transport number of 0.95 was obtained for SPES-TWM, which is comparable to the Nafion-117 membrane. The proton conductivity of both membranes increased as the temperature increased. The maximum proton conductivity of 6.3 mScm−1 was observed for SPES-TWM at 60 °C.

Eco-friendly, low-cost, and antibacterial PEM boosts microbial fuel cell performance: Power generation and wastewater treatment

The performance of microbial fuel cells (MFCs) relies significantly on the proton exchange membrane (PEM). While effective, commercial options like Nafion 117 are costly and possess inherent weaknesses. Improving methods of PEMs are generally used, requiring spending energy and money and causing harmful and toxic chemicals to enter the environment. This study introduces an innovative approach by enhancing sulfonated polyether sulfone (SPES) properties using Falcaria vulgaris extract, offering a simple, environmentally friendly, cost-effective solution. The resulting green functionalized SPES membranes (GFSPESs) were evaluated in dual-chamber MFCs for energy production and textile wastewater treatment. SPES membranes were fabricated through a phase inversion process and subsequently functionalized using dip-coating, heating, and UV irradiation. Comprehensive analysis, including FTIR, EDS, SEM, and XPS, investigated the physicochemical structure of the PEMs. The plant extract exhibited notable benefits, enhancing hydrophilicity, proton conductivity, and antibacterial capability of the PEMs. The MFC with GFSPES-12 achieved a peak power output of 86.3 mW/m2 and a maximum current of 327 mA/m2, surpassing the performance of Nafion 117 and the bare SPES membranes. GFSPES-12 also exhibited a maximum ion exchange capacity (1.89 meq/g) and proton conductivity (2.98 mS/cm). In textile wastewater treatment, the GFSPESs demonstrated improved COD removal (96.12 %) and higher coulombic efficiency (42.23 %). Notably, GFSPES-12 exhibited an antibacterial efficiency exceeding 93.5 %. These findings affirm the efficient functionality of GFSPES membranes in dual-chamber MFCs, offering a promising and sustainable alternative for energy production and wastewater treatment.

Effect of Plasma pretreatment and Graphene oxide ratios on the transport properties of PVA/PVP membranes for fuel cells

In this study, a novel proton-conducting polymer electrolyte membrane based on a mixture of polyvinyl alcohol (PVA)/polyvinyl pyrrolidone (PVP) (1:1) mixed with different ratios of graphene oxide (GO) and plasma-treated was successfully synthesized. Dielectric barrier dielectric (DBD) plasma was used to treat the prepared samples at various dose rates (2, 4, 6, 7, 8, and 9 min) and at fixed power input (2 kV, 50 kHz). The treated samples (PVA/PVP:GO wt%) were soaked in a solution of styrene and tetrahydrofuran (70:30 wt%) with 5 × 10−3 g of benzoyl peroxide as an initiator in an oven at 60 °C for 12 h and then sulfonated to create protonic membranes (PVA/PVP-g-PSSA:GO). The impacts of graphene oxide (GO) on the physical, chemical, and electrochemical properties of plasma-treated PVA/PVP-g-PSSA:x wt% GO membranes (x = 0, 0.1, 0.2, and 0.3) were investigated using different techniques. SEM results showed a better dispersion of nanocomposite-prepared membranes; whereas the AFM results showed an increase in total roughness with increasing the content of GO. FTIR spectra provide more information about the structural variation arising from the grafting and sulfonation processes to confirm their occurrence. The X-ray diffraction pattern showed that the PVA/PVP-g-PSSA:x wt% GO composite is semi-crystalline. As the level of GO mixing rises, the crystallinity of the mixes decreases. According to the TGA curve, the PVA/PVP-g-PSSA:x wt% GO membranes are chemically stable up to 180 °C which is suitable for proton exchange membrane fuel cells. Water uptake (WU) was also measured and found to decrease from 87.6 to 63.3% at equilibrium with increasing GO content. Ion exchange capacity (IEC) was calculated, and the maximum IEC value was 1.91 meq/g for the PVA/PVP-g-PSSA: 0.3 wt% GO composite membrane. At room temperature, the maximum proton conductivity was 98.9 mS/cm for PVA/PVP-g-PSSA: 0.3 wt% GO membrane. In addition, the same sample recorded a methanol permeability of 1.03 × 10−7 cm2/s, which is much less than that of Nafion NR-212 (1.63 × 10−6 cm2/s). These results imply potential applications for modified polyelectrolytic membranes in fuel cell technology.

Removal of Cu2+, Pb2+ , And Ni 2+ Ions From Simulated Waste Water By Ion Exchange Method On Zeolite And Purolite C105 Resin

The removal of heavy metal ions from wastewater by ion exchange resins ( zeolite and purolite C105), was investigated. The adsorption process, which is pH dependent, shows maximum removal of metal ions at pH 6 and 7 for zeolite and purolite C105 for initial metal ion concentrations of 50-250 mg/l, with resin dose of 0.25-3 g. The maximum ion exchange capacity was found to be 9.74, 9.23 and 9.71 mg/g for Cu2+, Pb2+, and Ni2+ on zeolite respectively, while on purolite C105 the maximum ion exchange capacity was found to be 9.64 ,8.73 and 9.39 for Cu2+, Pb2+, and Ni2+ respectively. The maximum removal was 97-98% for Cu2+ and Ni2+ and 92- 93% for Pb2+ on zeolite, while it was 93-94% for Cu2+, 96-97% for Ni2+, and 87-88% for Pb2+ on purolite C105. The obtained sorption affinity sequence was Cu 2+> Ni2+> Pb2+ in both resins. Langmuir isotherm expressions were found to give better fit to the experimental data compared to Freundlich and BET models. Kinetic data correlated well with Lagergren first order kinetic model, indicating the reversible reaction with an equilibrium being established between liquid and solid phase.

The correlation of sulfonation reaction kinetics with the degree of sulfonation (DS) and its effects on microstructure and morphology of electrospun fibers for the membrane of fuel cells.

Sulfonation is among the frequently used surface modification methods to endow new surface properties on polymer fibers. Direct sulfonation is the simplest chemical modification via incorporation of sulfonate functional groups onto fibers' surfaces at ordinary conditions. However, the process of functionalization compromises other properties of the electrospun membrane due to the extent of sulfonation reaction that occurred. This study was carried out to determine the effects on microstructure and morphology of crosslinked electrospun polybenzoxazine (PBz) fibers by correlating the reaction kinetics using a specific reaction parameter with the degree of sulfonation (DS). The kinetics of sulfonation reaction for PBz fibers is an electrophilic-based, first-type substitution mechanism where only one sulfonic acid (-SO3H) group is attached to each of the repeating units in the aromatic structure of PBz under ordinary conditions. From a previous study, the rate of change of ion exchange capacity (IEC) was derived as a logarithmic correlation that increased rapidly for some time and became constant. This study employed the derived empirical relationship based on reaction kinetics to correlate the degree of sulfonation (DS) with IEC at varying reaction time. DS was calculated as 55%, 66% and 77%, for 3, 6 and 24 h, respectively. The maximum IEC of 2.71 with the corresponding DS of 100% was obtained theoretically but since sulfonation reaction kinetics at ordinary conditions proceeds at slower phase, it can only attain 86% DS with maximum IEC of 2.44 at a calculated time of 48 h. Sulfonation was confirmed by the functional groups present in the structural composition of PBz fibers using ATR-FTIR which were quantified based on the absorbance in the IR spectra showing an increased peak height with increased reaction time for the first 6 h. Morphological analyses using SEM images revealed an increase in fiber diameter with increased sulfonation time. In addition, the higher reaction time showed the effects of longer acid exposure which compromised the fibers' structural integrity with the presence of broken fibers and defects on fibers' surfaces after 24 h. The electrospun PBz fibers sulfonated for 6 h achieved the highest IEC value with DS of 66% which was enough to attain the balance of degree of sulfonation with electrochemical and morphological properties.

Incorporating silica-magnetite synthesized from natural resources into the cation exchange membranes

Inorganic material-incorporated cation exchange membranes (CEMs) with improved properties have drawn attention for reverse electrodialysis (RED). This paper deals with improving CEMs properties by incorporating silica–magnetite inorganic materials from natural resources. First, silica and magnetite were extracted from rice husk and iron sand, respectively. CEMs were prepared using the phase inversion method by incorporating various ratios. The results showed that both silica and magnetite were in micron size with yields of 76.6% and 59.2% wt., respectively. The CEMs containing magnetite materials showed higher ion exchange capacity (IEC) and ionic conductivity than PVC membranes. However, they had a greater swelling degree. The presence of silica reduced the swelling degree from 18.38% to 7.15% leading to membrane strengthening. A maximum IEC and conductivity of CEMs of 0.26 meq/g and 0.524 S/cm were obtained for the membrane prepared with a SiO2/Fe3O4 ratio of 0:4, respectively. However, considering all aspects, the addition of a SiO2/Fe3O4 ratio of 1:3 was the most significant for increasing the fixed cation density and conductivity by 27.49% and 2815%, respectively, compared to other ratios. Thus, this SiO2/Fe3O4 ratio (1:3) should be considered for practical implementation. Performance examination using RED confirmed that the PVC/SiO2/Fe3O4 can be used as CEM for power generating and had comparable performance to commercial membrane.

Design and synthesis of side-chain optimized poly(2,6-dimethyl-1,4-phenylene oxide)-g-poly(styrene sulfonic acid) as proton exchange membrane for fuel cell applications: Balancing the water-resistance and the sulfonation degree

Side-chain optimized poly (2,6-dimethyl-1,4-phenylene oxide)-g-poly (styrene sulfonic acid) (PPO-g-PSSA) is designed with balanced water-resistance and sulfonation degree. The PPO-g-PSSA is synthesized by controlled atom-transfer radical polymerization (ATRP) from brominated poly (2,6-dimethyl-1,4-phenylene oxide) (PPO-xBr) and ethyl styrene-4-sulfonate and followed by hydrolysis. A series of PPO-g-PSSA are prepared possessing different bromination degree (x) of PPO-xBr and polymerization degree (m) of the side-chains and the water-resistances of the fabricated membranes are investigated. The results show that a PPO-g-PSSA at relatively low x (x < 0.2) and high m (m > 4) exhibits good balance between the water-resistance and the sulfonation degree. Namely, it displays suitable proton conductivity with compromised water-resistance. Moreover, a maximum ion exchange capacity (IEC) of 3.24 mmol g−1 is reached without the sacrifice of water-resistance. In addition, PPO-g-0.08PSSA-13 and PPO-g-0.14PSSA-4 are chosen characterized by thermogravimetric analysis, proton conductivities and mechanical properties. At 90% RH, the optimized PPO-g-0.08PPSA-13 possesses a proton conductivity of 37.9 mS cm−1 at 40 °C and 45.5 mS cm−1 at 95 °C, respectively.

Sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene based membranes containing CuO@g-C3N4 embedded with 2,4,6-triphenylpyrylium tetrafluoroborate for fuel cell applications.

New series of polymer composite membranes were prepared from sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (S-PSEBS) and copper oxide loaded in graphitic carbon nitride (CuO@N-C) embedded with an ionic liquid, 2,4,6-triphenylpyrylium tetrafluoroborate. The structural and physicochemical properties of the composite membranes were studied in detail. Electrolyte membrane loaded with 8.0 wt% of CuO@N-C exhibited the maximum ion-exchange capacity of 3.1 meq. g-1, whereas that of the pristine membrane was restricted to 1.8 meq. g-1. From the TGA profile of the composite membrane, it was found to exhibit adequate thermal stability to be employed as electrolyte in fuel cells. Proton conductivity of the composite membranes was found to be in the range between 0.0179 S cm-1 and 0.0229 S cm-1. Indeed, the substantial results achieved with the S-PSEBS/CuO@N-C composite membranes were indicative of the notable features of the membranes for use in fuel cells.

Rapid and selective removal of Cs+ from water by layered potassium antimony thiostannate

137Cs is radioactive and highly hazardous to human health and the environment and its efficient removal from water is still challenging. In this study, potassium antimony tin sulfide (KATS-2) was synthesized using a hydrothermal method and utilized for the first time for cesium removal from water. KATS-2 showed a high maximum ion exchange capacity (358 mg g−1) and distribution coefficient (1.59 × 105 mL g−1) toward Cs+. In particular, KATS-2 showed rapid ion exchange kinetics and reached the adsorption equilibrium within 5 min with 99% removal efficiency. The adsorption was good at a wide active pH range (1–12) even in extreme alkaline conditions (Kd = 3.26 × 104 mL g−1 at pH 12). The effect of coexisting ions was also investigated, and a high selectivity toward Cs+ was maintained even in artificial seawater (Kd = 3.28 × 103 mL g−1). Powder X-ray diffraction and thermogravimetric analysis demonstrated that KATS-2 was chemically and thermally stable. The results showed that owing to its excellent adsorption performance as well as chemical and thermal stability, KATS-2 is a promising adsorbent for Cs+ removal from contaminated water.

ZrO2 incorporated polysulfone anion exchange membranes for fuel cell applications

Novel imidazolium functionalized polysulfone (ImPS) membranes modified with zirconia (ZrO2) were synthesized through solution casting technique. Structural, morphological, thermal and mechanical analysis of the composite membranes confirmed adhesion and property enhancement caused by ZrO2. Water absorption investigations revealed better water absorption of the ImPS/ZrO2 membranes with intact morphology. Maximum ion exchange capacity and ionic conductivity for the composite membranes were obtained as 2.84 mmol/g and 80.2 mS/cm (50 °C) which was 21% and 47% higher as compared to pure ImPS membrane. Alkaline stability of the blend membranes was increased due to strong interaction between ZrO2 and ImPS molecules. Fuel cell performance using Pt/C catalysts exhibited OCP and power density elevation with incremental amounts of ZrO2 in the composite membrane composition. ImPS membrane with 10% ZrO2 recorded a highest OCP and power density of 1.04 V and 270 mW/cm2 which was 35% and 39% higher than the pure ImPS. Thus, the anion exchange membranes developed by ImPS/ZrO2 blending could be suiting well for alkaline fuel cells applications.

Investigate the adsorption of cesium ion (Cs+) on Zn2[Fe(CN)6] AND Zn3[Fe(CN)6]2 nanoparticles

Adsorption of Cs+ ion from aqueous solution by Zn2[Fe(CN)6] and Zn3[Fe(CN)6]2 nanoparticle, and the effect of experimental conditions on the adsorption were investigated. Preliminary results showed that two materials were very efficient as an absorbent. Zn2[Fe(CN)6] and Zn3[Fe(CN)6]2 nanoparticle adsorbents for removal Cs+ion from solution have been successfully synthesized. Comparison between two materials, the Cs + ion adsorption capacity of Zn2[Fe(CN)6] was higher than Zn3[Fe(CN)6]2 and the reaction time was shorter. The adsorption equilibrium time of Zn3[Fe(CN)6]2 was about 20 hours, and the suitable pH range 3-7 while the Zn2[Fe(CN)6] was 15 minutes. The Cs+ ion absorption by Zn2[Fe(CN)6] nanoparticle follow the ion exchange mechanism, the best exchange capacities of the material were in the pH 3-5 range, ion exchange capacity depended on the pH, the maximum ion exchange capacity of the material at pH = 4 was 1.01 meq (Cs+) / g. After 15 min, about 98% of initial Cs+ ion concentration was removed from the solution; the adsorption data did not accord with Langmuir and Freundlich isotherms. The high adsorption capacity and good performance on other aspects, make the Zn2[Fe(CN)6] nanoparticle a promising adsorbent for the removal of Cs+ ion from water.

Investigating the adsorption of cesiun ion (Cs+) on cobalt hexacyanoferrate coated magnetite nanoparticles

Co2[Fe(CN)6]/Fe3O4 nanoparticle adsorbent for ion cesium (Cs+) sorption was prepared by a chemical co-precipitation method. The magnetization of the materials makes them to be separated easyly from an aqueous solution by an external magnetic field. The ion Cs+ absorption by Co2[Fe(CN)6]/Fe3O4 nanoparticle follow the ion exchange mechanism, ion exchange capacity depends on the pH, the maximum ion exchange capacity of the material at pH = 4 is 0.40 meq (Cs+)/ g. After 15 min, about 98% of initial ion Cs+ concentration was removed from the solution, the adsorption could be described by Langmuir and Freundlich isotherms. The high adsorption capacity and good performance on other aspects, make the Co2[Fe(CN)6]/Fe3O4 nanoparticle a promissing adsorbent for the removal of ion Cs+ from water.

Synthesis of Polyketone Anion Ion Exchange Fibers by Paal-Knorr Reaction and Its Physico-Chemical Properties

In this study, polyketone anion exchange fibers were synthesized by the amination of polyketone via a Paal-Knorr reaction and a quaternization reaction. The amination reaction proceeded at different reaction times and amine N,N-dimethylethylene diamine (DME) concentrations. The ion exchange capacity (IEC) and water uptake (W.U.) increased with increasing amination reaction time and DME concentration, and the maximum IEC and W.U. were 1.03 meq/g and 19.2%, respectively. The tensile strength decreased significantly with increasing amination time and amine concentration. TGA showed that the thermal decomposition temperature of the fibers was 220 °C. The HCl gas adsorption properties of the aminated polyketone ion exchange fibers were evaluated, and the HCl gas removal efficiency remained at 100% in 40 min at 300 ppm.

One-pot preparation and characterization of lignin-based cation exchange resin and its utilization in Pb (II) removal

Lignin is a renewable source of aromatics, and the conversion of lignin to chemicals, fuels and materials is very attractive. Herein, a novel lignin-based cation exchange resin (LBR) was easily synthesized through an economical one-pot method. Results demonstrated that the sulfonic acid groups were successfully introduced into the skeleton of the resins, and the S contents and swelling capacity of the prepared LBRs gradually increased with the increment of the sulfonation reagents dosage. A maximum ion-exchange capacity of 2.26 mmol/g was achieved for the LBR obtained at 120 °C for 4 h with a molar ratio of phenol to formaldehyde (P:F) of 1:5 (SSPL-0.50), which was comparable to the commercial phenol type cation exchange resin. Furthermore, the SSPL-0.50 exhibited a high adsorption capacity (167.2 mg/g) for Pb (II) removal. The LBR can be considered as a promising substitute for the petroleum-based ion exchange resin in the purification of wastewater.

Preparation and characterization of proton exchange membrane by UV photografting technique

Ultraviolet (UV)-induced graft copolymerization of glycidyl methacrylate GMA onto poly(ethylene terephthalate) (PET) films and the subsequent sulfonation on the monomer units in the grafting chain using sulfuric acid were carried out to prepare proton exchange membranes (PEMs) for fuel cells. A maximum grafting value of 23.5% was found for 15 vol% GMA after 4-h radiation time. Optimum concentration of sulfuric acid was selected for the sulfonation reaction to be 1 mol/L based on the degree of sulfonation and the tensile strength studies of the membrane. The radiation grafting and the sulfonation have been confirmed by titrimetric and gravimetric analysis as well as FTIR spectroscopy. The maximum ion exchange capacity (IEC) of 2.085 meq g−1 was found at 46.99% degree of sulfonation and the maximum proton conductivity was found to be 60.35 mS cm−1 at 30 °C and relative humidity of 100%. The various physical and chemical properties of the PEMs such as water uptake, mechanical strength, thermal durability, free-volume content, and methanol permeability were also studied as function of sulfuric acid concentration. To investigate the suitability of the prepared membrane for fuel cell applications, its properties were compared with those of Nafion 112 as standard membrane.

Synthesis, characterisation and ion exchange properties of hybrid organic–inorganic composite material: polyacrylamide zirconium (IV) iodosulphosalicylate

ABSTRACTContamination of groundwater by heavy metal is one of the most emerging and serious environmental problems. There are so many methods which are available to overcome these problems. Among various available methods, hybrid organic–inorganic ion exchange resin has become more popular due to certain advantages over other available conventional methods; hence, in the present proposed work, we synthesised a hybrid organic–inorganic composite material polyacrylamide zirconium (IV) iodosulphosalicylate by using the sol-gel technique. Synthesised resin was characterised by various methods like Infrared spectroscopy and Thermogravimetric analysis-Differential thermal analysis. Various samples of this ion exchange resin are prepared by changing the condition of synthesis, i.e. concentration of acrylamide to rationalise the ion exchange capacity of the synthesise hybrid organic–inorganic ion exchange resins. A mixture of 0.1 M potassium iodate, 0.1 M sulphosalicylic acid and 0.1 M acrylamide was added dropwise to 0.4 M zirconium oxychloride accompanied by constant stirring for 8 h using magnetic stirrer at 70°C to yield polyacrylamide zirconium (IV) iodosulphosalicylate with maximum ion exchange capacity. Ion exchange capacity of synthesised resin was determined by column method and the maximum ion exchange capacity was found for Pb(II). Determination of kd values shows that the resin was highly selective for Pb (II).The selectivity for Pb was also evaluated by using certain binary mixture separation such as Ni (II)-Pb(II), Cu(II)-Pb(II), Cd(II)-Pb(II), Sr(II)-Pb(II), Ba(II)-Pb(II),Zn(II)-Pb(II) and Mg(II)-Pb(II).

PREPARATION OF ANION-EXCHANGE CELLULOSE FOR THE REMOVAL OF CHROMATE

The quaternary ammonium group containing cellulose was prepared by the one-pot method and applied for the removal of chromate (CrO4 2- ) ions from aqueous solution. The prepared sorbent was characterized by using elemental analyzer and Fourier transform infrared (FTIR) spectroscopy. Its ion exchange behavior toward CrO4 2- ions was investigated as a function of sorbent dose and initial solution pH. The kinetic and sorption equilibrium experiments were also carried out in a batch system. Equilibrium data were best fitted with the Langmuir model and the maximum ion exchange capacity of the sorbent was found as 3.8 mg of CrO4 2- /g sorbent. Moreover, the removal of CrO4 2- is achieved within 5 minutes. Furthermore, the calculated thermodynamic parameters disclosed that the ion exchange reaction is feasible, spontaneous and exothermic. In addition, the CrO4 2- ions can be desorbed from the sorbent by 1.0 M HCl solution with 95% regeneration efficiency.

Dechlorination of molten chloride waste salt from electrorefining via ion-exchange using pelletized ultra-stable H-Y zeolite in a fluidized particle reactor

Dechlorination of eutectic LiCl–KCl based electrorefiner (ER) salt is reported via ion-exchange reaction with protonated ultrastable Y-type (USHY) zeolite bound into mechanically fluidized 45–250 μm diameter particles. Evidence of exchange of cations from the salt (Li+, K+, and fission product cations) into the zeolite lattice replacing H+ ions was found based on a change in unit cell size, ICP-MS, XRD and TEM–EDS in addition to detection of HCl off gas. Ion exchange reaction was carried out at 625 and 650 °C, temperatures above the melting point of eutectic LiCl–KCl. Experiments were carried out to optimize zeolite drying temperature, estimate maximum ion-exchange capacity, and determine the thermal stability of USHY zeolite. The results indicate over 90% dechlorination can be achieved without zeolite structure collapse at 625 °C. This provides a promising route to stabilizing waste from radioactive chloride salts into dechlorinated waste forms for permanent geologic disposal.

Sulfonated Poly(ether ether ketone) Doped with Ammonium Ionic Liquids and Nano-Silicon Dioxide for Polymer Electrolyte Membranes

Nano-silicon dioxide (SiO2) was incorporated into the matrix of sulfonated poly(ether ether ketone) (SPEEK)/ammonium ionic liquid (AIL) membranes by solution casting, with the aim of reducing ionic liquid leaching and any consequent decrease in proton conductivity. Fourier transform infrared (FTIR) spectra results indicate incorporation of the SPEEK matrix with AIL and nano-SiO2. Scanning electron microscopy (SEM) and X–ray diffraction (XRD) images revealed that incorporation of nano-SiO2 make the ternary composite membranes more flexible. The maximum ion exchange capacity (IEC) value was 3.25 meq/g, and the net structure formed by the nano-SiO2 not only retarded AIL leaching, but also increased the proton conductivity of the composite membranes. AIL leaching from the membranes was between 20% and 30%, which was lower than that of the SPEEK/AIL membrane. The maximum proton conductivity for the SPEEK/AIL/SiO2 membranes reached 10.73 mS/cm at 393 K.

Porous polymer derived ceramic (PDC)-montmorillonite-H3PMo12O40/SiO2 composite membranes for microbial fuel cell (MFC) application

Ceramic membranes can serve as viable alternatives to the less mechanically stable polymeric membranes utilized in microbial fuel cells (MFCs). In this work, a series of polymer-derived ceramic (PDC) proton exchange composite membranes with large ion exchange capacity (IEC) values, high cation transport numbers, and low oxygen diffusion coefficients have been synthesized at various pyrolysis temperatures using a pressing technique. These materials were composed of a polysiloxane matrix mixed with proton-conducting fillers such as montmorillonite and H3PMo12O40/SiO2 at different ratios. By tuning the average pore sizes of the membranes between 0.1 and 1 µm and their hydrophilic/hydrophobic characteristics, the maximum IEC of 0.6072 mequiv/g and cation transport number of 0.6988 were obtained, which is 67% and 72% of polymeric nafion performance, respectively. In addition, the minimal oxygen mass transfer coefficient achieved by this approach was equal to 5.62 × 10−4 cm/s, which is very close to the commercial nafion membrane value. The fabricated PDC composite membranes meet all the essential criteria required for their use in MFC applications and represent a high potential to overcome limitations of polymeric membrane.