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Hybrid composite membranes possess the desired properties than that of the pristine polymeric membranes for fuel cell applications. Phase inversion method was used to entrap silicotungstic acid (STA) particles in Sulfonated Poly Ether Ether Ketone (SPEEK) membranes as a source of protons having a high protonic conductivity at room temperature (0.02–0.1 S/cm). The physico-chemical properties of the hybrid membranes were characterized by SEM-EDX, line scanning, 3D non-contact profilometer, FTIR and XRD techniques. These membranes showed better ion exchange, proton conductivity values and were tested in single chamber microbial fuel cell (SCMFC). In addition, these membranes show decreased oxygen crossover and transport of cations other than protons. Among the various weight percentage (2.5%, 5%, 7.5% and 10%) of STA prepared composite membranes, 7.5% STA + SPEEK showed the highest power density of 207 mWm−2 compared to that of commercial Nafion 117 (47 mWm−2) in the same setup of SCMFC. Overall, the composite membranes proved to be excellent candidates as electrolytes for Microbial Fuel Cell (MFC) applications.

Rutile TiO 2 was synthesized using the sol gel method and used for the preparation of polymer composite electrolyte membrane of TiO 2 +SPEEK. The composite membranes prepared by solvent casting method showed improved oxygen mass transfer coefficient values and the transport of cations other than protons. The antifouling property of the composite membranes was observed in SEM images which were additionally supported by hemocytometer results. The improved ion exchange and water absorption capacity of composite membranes showed enhanced proton conductivity and electrochemical properties for the composite membranes. The prepared composite membranes were evaluated in single chamber microbial fuel cell and the results were compared with that of the Nafion 117 ® under similar conditions. The results revealed that all the prepared composite membranes showed higher maximum power density and current density than that of the commercially available Nafion117 ® . Among the prepared membranes, SPEEK+7.5% TiO 2 composite membrane showed the highest power density (98.1 mW/m 2 ) and current density (300 mA/m 2 ) along with high proton conductivity, antifouling property.

A new class of composite membranes was made based on sulfonated poly ether ether ketone (SPEEK) incorporated with micron-sized sulfonate styrene-crosslinked divinyl benzene-based cation exchange resin particles as fillers with desired properties of higher ion exchange capacity, lower oxygen crossover, lesser mono, and divalent alkali cation transport for microbial fuel cell (MFC) applications. Such cation exchange resin-based composite membranes showed good membrane homogeneity as revealed from SEM images. XRD patterns showed better amorphous nature for the composite membranes with increase in resin loading. FT-IR spectra of composite membranes showed the presence of hydrogen bonding between the sulfonated PEEK and resin. The effects of existence of hydrogen bonding in the properties of membranes such as water uptake, transport of cations other than proton, oxygen crossover, and proton conductivity were discussed. The composite membranes showed one order lesser oxygen mass transfer coefficient (K o) in the range of 10−6 cm/s when compared to Nafion membranes. The composite membranes were tested in a single chamber Pt/C-coated air cathode MFC with Escherichia coli as anodic microbial inoculum. With resin, the SPEEK composite membranes showed higher power density value of 410 mW/m2 for 7.5 % IER + SPEEK composite membrane compared to that of Nafion (47 mW/m2) and SPEEK (77 mW/m2) membranes with same configuration.

A zeolite (H-faujasite) incorporated SPEEK membrane was demonstrated as an effective proton exchange membrane for Microbial Fuel Cell (MFC) application. The proton conductive faujasite zeolite contains uniform channels with an effective diameter ∼0.74 nm that permits small ions but restricts large hydrated ions. In this work, SPEEK/zeolite membranes were prepared by a solvent evaporation method with different weight percentages (2.5%, 5%, 7.5%, 10%) of zeolite. The physico-chemical properties of the composite membranes such as water uptake, ion-exchange capacity, proton conductivity, dissolved oxygen crossover and transport of cations were studied for their suitability in MFC. A maximum proton conductivity of 0.178 × 10−2 S cm−1 was obtained for 7.5% zeolite + SPEEK. All the membranes were tested in a Single Chamber MFC (SCMFC) using E. coli inoculum and Pt/C as cathode catalyst. The 7.5% zeolite + SPEEK membrane showed the highest power density (176 mW m−2) compared to that of commercial Nafion and other composite membranes.

The influence of Fe3O4 in proton conductivity, oxygen crossover, water absorption and performance of Sulfonated Poly Ether Ether Ketone (SPEEK) matrix was studied in single chamber microbial fuel cell at various weight percentages (2.5%, 5%, 7.5%, 10%) of SPEEK/Fe3O4. The fabricated composite membranes were characterized by FT-IR, SEM, and XRD which were also tested for their surface roughness, water absorption, proton conductivity and transportation of cations were also studied for its suitability in microbial fuel cell operation. Escherichia coli (E. coli), an electrogenic bacteria, was used as the biocatalyst in anodic chamber and platinized carbon (Pt/C) was used as the catalyst in the air cathode. The low oxygen crossover, selective transfer of protons and water mediated proton hopping mechanism in Fe3O4 composite membrane (7.5% Fe3O4) resulted in a maximum power density of 104 mW m−2 which was higher than that of the power density of Nafion® 117 (47 mW m−2) under the same operating conditions. The results of the study suggested that SPEEK/Fe3O4 (7.5 wt%) composite membrane would be more commercially viable and efficient than the existing Nafion membranes for use in microbial fuel cells.

BackgroundThe application of polymeric materials in medical industry has grown drastically in the last two decades due to their various advantages compared to existing materials. The present research work emphases on the sol-gel technique to formulate the polymethyl methyl acrylate/polystyrene/silica composite membrane.MethodsThe characteristic of the composite was investigated through modern state art of instrumentation.ResultsThe functional groups attached to the polymer was absorbed by FTIR. The FTIR spectrum confirm that the blend was mixed thoroughly and the formation of unite intimately between the polymers. The membranes were observed by SEM for its surface homogeneity which depends upon the composition of the two blending polymers. The captured SEM images showed the formation of microcracks on the surface, which was evidently controlled by varying the constituent polymer ratios. The prepared blend membranes with 2:1 ratio of PMMA/PS/Si displayed higher water uptake compared to other blended membranes. The composite membranes had good hydroxyl apatite growth in SBF solution. Furthermore, the in vitro cytotoxicity studies carried out by MTT method, using RAW macrophage cells showed that all the samples exhibited excellent cell viability.ConclusionThe inflammatory response of composite with equal concentration of PMMA-PS were performed and observed no inflammation in comparison with control and other tested concentrations.

The influence of Multi Walled Carbon Nano Tube (MWCNT) in oxygen cross over, water absorption and performance of chitosan (CHIT) in Single Chamber Microbial Fuel Cell (SCMFC) was studied. CHIT and non covalently functionalized MWCNT with CHIT (CHIT–MWCNT) were prepared in the form of membranes and characterized using FTIR, XRD, DRS UV, CD, Raman, SEM and TEM to study the interaction of MWCNT with chitosan. CHIT–MWCNT showed lesser water absorption compared to that of CHIT. CHIT–MWCNT membrane showed oxygen mass transfer coefficient (2.66×10 −4 cm/s) one order less than that of CHIT (2.28×10 −3 cm/s). The prepared membranes were continuously tested in an in-house built Single Chamber Microbial Fuel Cell (SCMFC). The maximum power density obtained by CHIT–MWCNT composite membrane was higher compared to that of CHIT membrane obtained was 38.16 mW/m 2 and 46.94 mW/m 2 for CHIT and CHIT–MWCNT, respectively. The results of the study showed that the MWCNT incorporated chitosan composite membrane had strong influence on the properties and performance of CHIT in microbial fuel cell. Hence, CHIT–MWCNT is a promising candidate for application in microbial fuel cell.

The future economy is projected as hydrogen economy and fuel cells are set to become the energy source either replacing or augmenting the present oil based technology. A sulfonated poly ether ether ketone (SPEEK) membrane as the electrolyte for hydrogen sensor that operates at room temperature was developed in our lab. The electrolyte used was SPEEK, which is a proton conducting solid polymer membrane. The membranes were characterized using various available techniques like TGA, XRD, SEM, etc. The durability was studied using the Fenton’s reagent. The proton conducting ability was analyzed using impedance spectroscopy. The catalysts considered were platinum for the cathode and three different catalysts (Pt, Pt/Pd and Pd) for the anode. The MEAs were evaluated for their performance in hydrogen sensor and the one with platinum catalyst at the anode gave the best response among the three indicating its suitability for the SPEEK membrane for hydrogen sensor.

Sulfonated polystyrene ethylene butylene polystyrene (SPSEBS) membrane was prepared by evaporation casting method and was used as the Polymer Electrolyte Membrane (PEM) for PEM Fuel Cells (PEMFC). Suitability of the membrane for fuel cell studies was examined. This work analyses the optimization of operating parameters of the fuel cells such as cell temperature, flow rate and humidification temperature of anode gas (H2). Using Design of Experiments (DOE) number of trials to be conducted was identified. The parameters were optimised using the Taguchi method. The optimized value was then employed in the fuel cell setup and the cell performance was studied. The maximum fuel cell output was obtained at cell temperature of 70° C, flow rate of 0.4 lpm and humidification temperature of 70° C.

In this present study TiO2 supported metal catalysts (Pt/TiO2, Pt–Fe/TiO2) were prepared by liquid phase photo deposition method. The prepared catalysts were characterized electrochemically. X-ray Diffractometer (XRD) results showed the presence of metal particle deposition on TiO2. HR-SEM and TEM results confirmed the nano size of the metal particles and their uniform dispersion on the surface of TiO2. Electrochemical methods such as cyclic Voltammetry, linear sweep Voltammetry were used to study the stability and oxygen reduction properties of the synthesized TiO2 supported metal catalysts. The prepared catalysts were tested in Single Chamber Microbial Fuel Cell (SCMFC) with Escherichia coli of type DH5-α as bacterium. The power densities of Pt/TiO2 and Pt–Fe/TiO2 (110.5 and 136.8 mW/m2) were found to be higher compared to that of Pt/C (77 mW/m2) in MFC operation. The results visualized the better electro catalytic property for oxygen reduction in cathodic part of microbial fuel cell.