PDF Publication Title:
Text from PDF Page: 009
Molecules 2020, 25, 1712 9 of 44 where M is a cation of valence n, m is the number of water molecules and the sum of x and y is the total number of tetrahedra in the unit cell. Several authors [92,93] have claimed that zeolite membranes can be adopted for DMFC application. The approach of these studies was to take advantage of the molecular sieving property of zeolite to prevent methanol from passing through the membrane. However, a pure zeolite exhibits poor mechanical properties such as brittleness and fragility and hence is unsuitable for use as a membrane. Moreover, the performance of the zeolite composite membranes depends on the zeolite properties in terms of pore size and surface tension (hydrophobility or hydropholicity). It was reported that hydrophobic zeolites ensure low affinity to water so high permeability to methanol however hydrophilic zeolites lead to an opposite trend and therefore reduce methanol crossover [94]. When zeolites are combined with a polymer support (e.g., Nafion), the advantages of both polymer and zeolite are combined. Among the various type of zeolites, mordenite (MOR) and analcime (ANA) have attracted a lot of interest because they are hydrophilic substances which promote the adsorption of water, excluding alcohol, and provide a good proton pathway through the membrane. Prapainainara et al. [95] fabricated composite membranes with those two fillers studying and comparing their properties and performance. The authors claimed that the presence of the filler benefited the proton migration through the membrane whilst the homogeneous distribution of the filler contributed to block the flow of methanol through the membrane, leading to lower methanol permeability. The composite membrane with MOR filler gave better membrane properties, namely; higher proton conductivity and lower methanol permeability, than those using ANA filler. The best DMFC performance was achieved by MOR composite membrane with a maximum power density of 10.75 mW/cm2, 1.5 times higher than ANA membrane and two times higher than a commercial Nafion 117 membrane. To enhance the performance of MOR/Nafion, Prapainainara et al. [96] incorporated graphene oxide (GO) to the matrix. The authors used GO to modify the surface of MOR by increasing the surface hydrophilic functional groups resulting in better incorporation of MOR to Nafion and comparable chemical properties with those of pristine Nafion and MOR/Nafion. The use of GO led to better proton conductivity, 1.5 times higher than that of Nafion/MOR and Nafion 117 at 70 ◦C and it had the lowest methanol permeability too. The authors also tested the membrane in a single cell, obtaining a power density of 27.5 mW/cm2; almost 5 times than that of Nafion 117 at the same operating condition (1 M methanol, 70 ◦C). However, the operation lifetime was still not good enough for commercial applications. 2.1.3. Carbon Nanomaterial Fillers Graphene oxide (GO) was used as a filler in Nafion membranes because it allows easy proton transport and good water uptake due to its high surface area. The different oxygen groups such as epoxide, hydroxide, carbonyls and carboxyls converts GO into electrically insulating and hydrophilic material [97] while retaining other properties like mechanical strength, surface area, and gas impermeability. Graphene oxide has an excellent compatibility with Nafion so it can be adopted as a modifier to improve the selectivity (to allow the passage of specific species) and performance of such membranes. Choi, et al. [98] developed a composite GO/ Nafion membrane. The authors claimed that the compatibility between both components was guaranteed due to their strong interfacial attraction. GO enhanced thermal backbone and side chains stabilities due to the interaction between GO sheets and Nafion: the non-polar backbone of Nafion interacted with the hydrophobic structure of GO while the polar ionic clusters of Nafion with the hydrophilic groups of GO. Their study revealed that the permeability for methanol with just 0.5 wt.% of GO was reduced to 60.2% of Nafion 112 at 25 ◦C. However, the proton conductivity tests revealed an opposite trend showing a decrease with increasing the GO filler content and a loss of 55.3% in proton conductivity is reported with 2 wt. % GO loading. This was not completely unexpected as GO alone is not known to be an excellent proton conductor.PDF Image | Composite Polymers for Electrolyte Membrane Technologies
PDF Search Title:
Composite Polymers for Electrolyte Membrane TechnologiesOriginal File Name Searched:
molecules-25-01712.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)