The role of membrane ion exchange capacity on membrane|gas diffusion electrode interfaces: a half-fuel cell electrochemical study

2004 ◽  
Vol 567 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Titichai Navessin ◽  
Steven Holdcroft ◽  
Qianpu Wang ◽  
Datong Song ◽  
Zhongsheng Liu ◽  
...  
Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 914 ◽  
Author(s):  
Lucia Mazzapioda ◽  
Stefania Panero ◽  
Maria Assunta Navarra

Nafion composite membranes, containing different amounts of mesoporous sulfated titanium oxide (TiO2-SO4) were prepared by solvent-casting and tested in proton exchange membrane fuel cells (PEMFCs), operating at very low humidification levels. The TiO2-SO4 additive was originally synthesized by a sol-gel method and characterized through x-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and ion exchange capacity (IEC). Peculiar properties of the composite membranes, such as the thermal transitions and ion exchange capacity, were investigated and here discussed. When used as an electrolyte in the fuel cell, the composite membrane guaranteed an improvement with respect to bare Nafion systems at 30% relative humidity and 110 °C, exhibiting higher power and current densities.


2014 ◽  
Vol 666 ◽  
pp. 3-7
Author(s):  
Theampetch Apichaya ◽  
Paweena Prapainainar ◽  
Chaiwat Prapainainar

In this paper, proton conducting composite membranes of Nafion®-mordenite for direct methanol fuel cell (DMFC) were prepared using solution casting method. Mordenite, used as inorganic filler, was incorporated into Nafion polymer in order to improve membrane properties for DMFC application. Effect of solution casting temperature on resulting composite membranes was focused. The temperature of the membrane preparation was varied from 80 to 120°C. Properties and morphology of the resulting membranes including solubility, water uptake, ion – exchange capacity were investigated and reported. It was found that composite membrane prepared at 100°C gave the most alcohol resistance and mechanical stability membrane with 0.59% soluble. Furthermore, it gave highest ion – exchange capacity, 0.10 meq⋅g-1, which is 33% and 98% higher than the membranes prepared at 80°C and 120°C respectively.


Author(s):  
D. Vidhyeswari ◽  
A. Surendhar ◽  
S. Bhuvaneshwari

Abstract The aim of this study is to synthesis SPEEK composite proton exchange membrane with the addition of TiO2 nanofillers for microbial fuel cell application. SPEEK composite membrane with varying weight percentage of TiO2 (2.5, 5, 7.5 and 10%) was prepared to study the effect of TiO2 concentration on membrane performance. Synthesized composite membranes were subjected to various characterization studies such as FT-IR, XRD, Raman spectroscopy; TGA, UTM and SEM. Physico-chemical properties of membrane such as water uptake capacity, ion exchange capacity and thickness were also analyzed. 5% TiO2 – SPEEK composite membrane exhibited the higher water uptake capacity value and Ion exchange capacity value of 31% and 1.71 meq/g respectively. Performance of the MFC system with TiO2 – SPEEK membranes were evaluated and compared with the pristine SPEEK and Nafion membrane. 5% TiO2 – SPEEK membrane produced the higher power density (1.22 W/m2) and voltage (0.635 V) than the other membranes investigated. Efficacy of MFC in wastewater treatment was evaluated based on the chemical oxygen demand (COD), total organic carbon content and turbidity. Biofilm growth over the surface of the electrodes was also analyzed using scanning electron microscopy.


Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 395
Author(s):  
Jonathan Teik Ean Goh ◽  
Ainul Rasyidah Abdul Rahim ◽  
Mohd Shahbudin Masdar ◽  
Loh Kee Shyuan

The polymer electrolyte membrane (PEM) is a key component in the PEM fuel cell (PEMFC) system. This study highlights the latest development of PEM technology by combining Nafion® and ionic liquids, namely 2–Hydroxyethylammonium Formate (2–HEAF) and Propylammonium Nitrate (PAN). Test membranes were prepared using the casting technique. The impact of functional groups in grafting, morphology, thermal stability, ion exchange capacity, water absorption, swelling and proton conductivity for the prepared membranes is discussed. Both hybrid membranes showed higher values in ion exchange capacity, water uptake and swelling rate as compared to the recast pure Nafion® membrane. The results also show that the proton conductivity of Nafion®/2–HEAF and Nafion®/PAN membranes increased with increasing ionic liquid concentrations. The maximum values of proton conductivity for Nafion®/2–HEAF and Nafion®/PAN membranes were 2.87 and 4.55 mScm−1, respectively, equivalent to 2.2 and 3.5 times that of the pure recast Nafion® membrane.


2005 ◽  
Vol 152 (4) ◽  
pp. A796 ◽  
Author(s):  
Titichai Navessin ◽  
Michael Eikerling ◽  
Qianpu Wang ◽  
Datong Song ◽  
Zhongsheng Liu ◽  
...  

Author(s):  
Bruce C. Bunker ◽  
William H. Casey

Oxides comprise the most common ion-exchange materials on our planet, with the clay minerals alone, formed by the weathering of rock, having a total mass of around 1025 g. This mass represents almost one-third of the total mass of Earth’s crust and is more than six times the mass of Earth’s oceans. These fine-grained ion exchange materials play a major role in mediating the concentrations of ionic species found in freshwater, groundwater, and our oceans (see Chapter 18). Oxide ion exchangers are also of critical importance in removing contaminants from the environment. Nowhere is this role more apparent than in the removal and sequestration of radioactive elements such as 137Cs, 90Sr, and 99Tc, which are serious hazards present in nuclear wastes. Oxide ion exchangers exhibit several properties that make them materials of choice for treating nuclear wastes, including high selectivity, enhanced stability to radiation damage relative to organic exchangers, and the potential as materials to be condensed further into solid waste after they are loaded with radioactive species. Oxide exchangers are extremely useful for extracting valuable cations from complex fluids, such as the lithium used in our highest energy density batteries. Ion exchange also represents a pathway for creating unique nanomaterials, with applications including battery separators, catalysts, optical materials, magnets, and materials for drug delivery. Oxides materials can exhibit exceptional properties as both cation and anion exchangers for a wide range of separation and water treatment technologies. Although the total ion-exchange capacity of an oxide is important for some applications, such as the deionization of water, separations require the use of oxides and hydroxides having the highest degree of ion-exchange selectivity. For selectivity, oxides must be designed with specific sites that exhibit a much higher affinity for one ion than any other, which requires much more sophistication than just generating a net charge. Here, we describe the key factors that control both the capacity and selectivity of inorganic ion exchangers, including (1) the role of acid–base reactions in controlling surface charge and ion-exchange capacity, (2) the role of local charge distributions in determining ion-exchange selectivity, and (3) the effect of shape and selective solvation on enhancing that selectivity.


2013 ◽  
Vol 860-863 ◽  
pp. 803-806 ◽  
Author(s):  
Loh Kee Shyuan ◽  
Eng Lee Tan ◽  
Wan Ramli Wan Daud ◽  
Abu Bakar Mohamad

A diverse sulfonated polybenzimidazole copolymer (SPBI) as proton exchange membrane was synthesiszed via one-step high temperature polymerization method with 3,3-diaminobenzidine (DABD), 5-sulfoisophthalic acid (SIPA), 4,4-sulfonyldibenzoic acid (SDBA) and biphenyl-4,4-dicarboxylic acid (BDCA). The SPBI membrane was prepared through a direct hot-casting and in situ phase inversion technique. Characterization tests were carried out on the membranes including surface morphology, distribution of elements on the membrane, determination of functional groups, thermal stability, ion exchange capacity, water uptake rate and proton conductivity. The as-synthesized SPBI membrane displayed a smooth surface via scanning electron microscopy (SEM) analysis which is thermally stable up to 443 °C. The SPBI membrane showed higher water uptake rate (WUR) and proton conductivity though it had lower ion exchange capacity (IEC) value compared to recast Nafion membrane. The proton conductivity of the SPBI membrane with IEC of 0.60 mmol/g was 4.50 × 10-2 S/cm at 90 °C. This study shows that the SPBI membrane has great potential in polymer exchange membrane fuel cell (PEMFC) applications.


1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.


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