Comparison of alternative membranes to replace high cost Nafion ones in microbial fuel cells

Ionic Conductivity and Potential Application for Fuel Cell of a Modified Imine-Based Covalent Organic Framework

“…Remarkably, the conductivity value obtained for the LiCl@RT-COF-1 film at 313 K and 100 % RH is among the highest reported so far for both COFs and MOFs under similar operative conditions. 4,18,[27][28][29][30][31][32][33] In this sense, despite it being still very far from outperforming the ionic conductivity properties of Nafion ® , the use of imine-based COFs would overcome some limitations of this material in relation to its high manufacturing cost, difficult synthesis strategy and deactivation above 353 K. Moreover, it is well-known that COFs can be synthesized by different simple procedures and in general show extremely robust chemical and thermal stability thanks to the covalent bond formation. On the other hand, it should also be noted that the best conductivity values have been obtained blending crystalline porous frameworks (MOFs or COFs) with polymeric matrixes to yield mixed matrix membranes.…”

“…3 However, Nafion ® presents some limitations related to production cost, safety and environmental concerns that have to be solved with alternative membranes. 4,5 In this regard, crystalline porous materials have attracted great interest as proton-conducting materials. 6 Among them, Covalent Organic Frameworks (COFs) based on Schiff condensation reactions 7 are potential candidates that could fulfill these requirements.…”

“…6,[8][9][10][11] Indeed, crystalline laminar COFs can be considered promising platforms for the formation of ion conductive membrane materials as a result of the rational design of their structures, their easy functionalization and their inherent properties like low mass density, high thermal and chemical stability and permanent porosity. 4,[11][12][13][14][15][16] Furthermore, despite a few COFs showing ionic conductivities as high as 3.96×10 -2 S cm -1 , at room temperature, [17][18][19] convenient methodologies of synthesis, processing and integration of these materials on supports are on their infancy. 5,[20][21][22] In this sense, we have recently published the room temperature one-pot condensation reaction of 1,3,5-tris(4-aminophenyl)benzene with 1,3,5benzenetricarbaldehyde to yield RT-COF-1 and RT-COF-1Ac.…”

Tailored Assembly of Molecular Water Oxidation Catalysts on Photoelectrodes for Artificial Photosynthesis

“…[116] Although they showed that PEC performance can be engineered by controlling functional groups on ligand molecules, the use of Nafion is impractical for large scale applications due to its high cost. [117][118][119][120][121] For the immobilization on hydrophobic photoelectrodes or electrodes, hydrophobic polyaromatic functional groups can also be utilized as a surface anchoring group. [122][123][124] However, one can easily expect that this approach would have limited applications, as most artificial photosynthetic reactions are performed in aqueous solutions and that hydrophobic interactions are vulnerable to aggregation or disassembly.…”

Architectural engineering of bioelectrochemical systems from the perspective of polymeric membrane separators: A comprehensive update on recent progress and future prospects

“…Relevant estimations for various materials can be found in the paper of Dhar and Lee [15] and it can be drawn that further efforts have to be invested to attain the reduction of costs [18]. In this aspects, apart from artificially designed and synthetized polymers, naturally-occurring polymers and relatively cheap materials such as cotton fabric combined with PVA-PVDF [189], gelatin and alginate [190], agar [191], rubber [192], biodegradable bag [193], cellulose-derivative [121], carrageenan [194], ceramics [68,[195][196][197][198][199], Jcloth (a macroporous filter) [200] have been also employed as membranes/separators with various degrees of success in BES and hence, may present a path in the R&D of membranes/separators for cost reduction purposes.…”