Journal articles on the topic 'Reactive electrochemical membranes'
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Yang, Kui, Hui Lin, Shangtao Liang, Ruzhen Xie, Sihao Lv, Junfeng Niu, Jie Chen, and Yongyou Hu. "A reactive electrochemical filter system with an excellent penetration flux porous Ti/SnO2–Sb filter for efficient contaminant removal from water." RSC Advances 8, no. 25 (2018): 13933–44. http://dx.doi.org/10.1039/c8ra00603b.
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Misal, Saurabh N., Meng-Hsuan Lin, Shafigh Mehraeen, and Brian P. Chaplin. "Modeling electrochemical oxidation and reduction of sulfamethoxazole using electrocatalytic reactive electrochemical membranes." Journal of Hazardous Materials 384 (February 2020): 121420. http://dx.doi.org/10.1016/j.jhazmat.2019.121420.
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Winter, Lea R., and Menachem Elimelech. "(Invited) Electrified Membranes for Transformation of Nitrate in Wastewaters." ECS Meeting Abstracts MA2022-01, no. 40 (July 7, 2022): 1798. http://dx.doi.org/10.1149/ma2022-01401798mtgabs.
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The release of nitrate to the environment from wastewater effluent and agricultural runoff contributes to groundwater contamination, harmful algal blooms, and disruption of biogeochemical nitrogen flows. Typical treatment methods are based on nitrate separation, which produces waste streams that are often discharged to the environment. Alternatively, nitrate conversion via electrochemical reduction eliminates the production of concentrated waste streams while avoiding the addition of reductant or hole scavenger chemicals to accomplish the reaction. However, major challenges for nitrate removal from water via electrochemical conversion involve reducing the use of expensive precious metal electrocatalysts while also improving the reaction activity and selectivity, catalyst stability, and mass transport of nitrate to electrocatalyst active sites. The use of electrochemical membranes as multifunctional porous flow-through electrodes could potentially address these challenges based on improved mass transport and altered kinetics under flow conditions within membrane pores. Conductive membranes were fabricated using polymers combined with carbonaceous materials such as reduced graphene oxide (rGO) and carbon nanotubes. The rGO was functionalized with non-precious transition metal oxynitride electrocatalysts, where these catalysts showed higher nitrate conversion activity compared to the unsupported transition metal nitrides. The influence of catalyst materials, membrane fabrication process, and filtration conditions on nitrate reduction activity and selectivity were evaluated. In addition to the environmental impacts of closing the nitrogen loop by converting nitrate into innocuous N2, selective nitrate reduction to ammonia provides opportunities for recovery as fertilizer or carbon-free renewable energy storage. The prospects for reactive nitrogen recovery based on nitrate electrochemical conversion to ammonia were analyzed for various potential source waters.
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Trellu, Clément, Brian P. Chaplin, Clémence Coetsier, Roseline Esmilaire, Sophie Cerneaux, Christel Causserand, and Marc Cretin. "Electro-oxidation of organic pollutants by reactive electrochemical membranes." Chemosphere 208 (October 2018): 159–75. http://dx.doi.org/10.1016/j.chemosphere.2018.05.026.
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Almassi, Soroush, Zhao Li, Wenqing Xu, Changcheng Pu, Teng Zeng, and Brian P. Chaplin. "Simultaneous Adsorption and Electrochemical Reduction of N-Nitrosodimethylamine Using Carbon-Ti4O7Composite Reactive Electrochemical Membranes." Environmental Science & Technology 53, no. 2 (December 14, 2018): 928–37. http://dx.doi.org/10.1021/acs.est.8b05933.
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Gu, Liankai, Yonghao Zhang, Weiqing Han, and Kajia Wei. "Membrane Fouling and Electrochemical Regeneration at a PbO2-Reactive Electrochemical Membrane: Study on Experiment and Mechanism." Membranes 12, no. 8 (August 22, 2022): 814. http://dx.doi.org/10.3390/membranes12080814.
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Membrane fouling and regeneration are the key issues for the application of membrane separation (MS) technology. Reactive electrochemical membranes (REMs) exhibited high, stable permeate flux and the function of chemical-free electrochemical regeneration. This study fabricated a micro-filtration REM characterized by a PbO2 layer (PbO2-REM) to investigate the electro-triggered anti-fouling and regeneration progress within REMs. The PbO2-REM exhibited a three-dimensional porous structure with a few branch-like micro-pores. The PbO2-REM could alleviate Humic acid (HA) and Bisphenol A (BPA) fouling through electrochemical degradation combined with bubble migration, which achieved the best anti-fouling performance at current density of 4 mA cm−2 with 99.2% BPA removal. Regeneration in the electro-backwash (e-BW) mode was found as eight times that in the forward wash and full flux recovery was achieved at a current density of 3 mA cm−2. EIS and simulation study also confirmed complete regeneration by e-BW, which was ascribed to the air–water wash formed by bubble migration and flow. Repeated regeneration tests showed that PbO2-REM was stable for more than five cycles, indicating its high durability for practical uses. Mechanism analysis assisted by finite element simulation illustrated that the high catalytic PbO2 layer plays an important role in antifouling and regeneration.
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Zaky, Amr M., and Brian P. Chaplin. "Porous Substoichiometric TiO2 Anodes as Reactive Electrochemical Membranes for Water Treatment." Environmental Science & Technology 47, no. 12 (June 5, 2013): 6554–63. http://dx.doi.org/10.1021/es401287e.
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Guo, Lun, Yin Jing, and Brian P. Chaplin. "Development and Characterization of Ultrafiltration TiO2 Magnéli Phase Reactive Electrochemical Membranes." Environmental Science & Technology 50, no. 3 (January 20, 2016): 1428–36. http://dx.doi.org/10.1021/acs.est.5b04366.
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Skolotneva, Ekaterina, Marc Cretin, and Semyon Mareev. "A Simple 1D Convection-Diffusion Model of Oxalic Acid Oxidation Using Reactive Electrochemical Membrane." Membranes 11, no. 6 (June 7, 2021): 431. http://dx.doi.org/10.3390/membranes11060431.
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In recent years, electrochemical methods utilizing reactive electrochemical membranes (REM) have been recognized as the most promising technologies for the removal of organic pollutants from water. In this paper, we propose a 1D convection-diffusion-reaction model concerning the transport and oxidation of oxalic acid (OA) and oxygen evolution in the flow-through electrochemical oxidation system with REM. It allows the determination of unknown parameters of the system by treatment of experimental data and predicts the behavior of the electrolysis setup. There is a good agreement in calculated and experimental data at different transmembrane pressures and initial concentrations of OA. The model provides an understanding of the processes occurring in the system and gives the concentration, current density, potential, and overpotential distributions in REM. The dispersion coefficient was determined as a fitting parameter and it is in good agreement with literary data for similar REMs. It is shown that the oxygen evolution reaction plays an important role in the process even under the kinetic limit, and its contribution decreases with increasing total organic carbon flux through the REM.
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Gayen, Pralay, Chen Chen, Jeremiah T. Abiade, and Brian P. Chaplin. "Electrochemical Oxidation of Atrazine and Clothianidin on Bi-doped SnO2–TinO2n–1 Electrocatalytic Reactive Electrochemical Membranes." Environmental Science & Technology 52, no. 21 (September 21, 2018): 12675–84. http://dx.doi.org/10.1021/acs.est.8b04103.
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Almassi, Soroush, Pamela Rose V. Samonte, Zhao Li, Wenqing Xu, and Brian P. Chaplin. "Mechanistic Investigation of Haloacetic Acid Reduction Using Carbon-Ti4O7 Composite Reactive Electrochemical Membranes." Environmental Science & Technology 54, no. 3 (December 26, 2019): 1982–91. http://dx.doi.org/10.1021/acs.est.9b06744.
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Santos, Melissa C., Yossef A. Elabd, Yin Jing, Brian P. Chaplin, and Lei Fang. "Highly porous Ti4 O7 reactive electrochemical water filtration membranes fabricated via electrospinning/electrospraying." AIChE Journal 62, no. 2 (November 24, 2015): 508–24. http://dx.doi.org/10.1002/aic.15093.
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Chmayssem, Ayman, Ibrahim Shalayel, Stéphane Marinesco, and Abdelkader Zebda. "Investigation of GOx Stability in a Chitosan Matrix: Applications for Enzymatic Electrodes." Sensors 23, no. 1 (January 1, 2023): 465. http://dx.doi.org/10.3390/s23010465.
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In this study, we designed a new biosensing membrane for the development of an electrochemical glucose biosensor. To proceed, we used a chitosan-based hydrogel that entraps glucose oxidase enzyme (GOx), and we crosslinked the whole matrix using glutaraldehyde, which is known for its quick and reactive crosslinking behavior. Then, the stability of the designed biosensors was investigated over time, according to different storage conditions (in PBS solution at temperatures of 4 °C and 37 °C and in the presence or absence of glucose). In some specific conditions, we found that our biosensor is capable of maintaining its stability for more than six months of storage. We also included catalase to protect the biosensing membranes from the enzymatic reaction by-products (e.g., hydrogen peroxide). This design protects the biocatalytic activity of GOx and enhances the lifetime of the biosensor.
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Kolmakov, Andrei A. "(Invited) Operando Scanning Electron and Photoelectron Spectromicroscopy to Study the Nucleation and Growth Phenomena in Liquid and Reactive Solid Electrolytes: The Technique Development." ECS Meeting Abstracts MA2022-01, no. 23 (July 7, 2022): 1153. http://dx.doi.org/10.1149/ma2022-01231153mtgabs.
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Nucleation and growth (NG) phenomena play a central role in a variety of applications spanning from the back end of line (BEOL) microfabrication to environmental remediation and energy devices performance. Therefore, the development of analytical metrologies, capable to access these phenomena with the high chemical, spatial and temporal resolution is amongst the key tasks of the research community. Probing nucleation and growth phenomena in situ, using traditional high analytical power tools such as SEM, XPS, AES, SPEM, and PEEM, under realistic sample environments, is a great aim but also an experimental challenge due to the apparent sample-to-detector “pressure gap”. Implementation of the electron transparent membranes that separate the reactive, liquid, or dense gaseous sample environments from the high vacuum instrumentation, in principle, resolves this impediment thus the standard analytical surface science equipment can be used. The sample and or device, therefore, need to be covered or encapsulated with a mechanically robust electron transparent impermeable membrane. The thickness of such a membrane defines the energy range and broadening of the transmitted electrons and, therefore, the thinnest membranes such as those made of 2D materials are desirable. Here, using variable pressure SEM, we exemplify the sensitivity of electrochemically driven NG processes to the composition of the ambient environment. Using model liquid electrolytes, we review the capabilities, advantages, and limitations of the graphene membrane-based liquid cells to probe NG processes with electron spectromicroscopy. In particular, we discuss graphene-cupped single orifice and microchannel arrays (MCA), and their applications for electrochemical polarization, nucleation, and growth studies using SEM, AES, SPEM, and PEEM. In addition to local spectromicroscopy, MCA-like designs enable application of high throughput combinatorial data mining algorithms to collect multi-dimensional/ hyperspectral datasets. The experimental artifacts and major limitation of the technique related to radiation damage of the sample will be discussed.
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Mareev, Semyon, Ekaterina Skolotneva, Marc Cretin, and Victor Nikonenko. "Modeling the Formation of Gas Bubbles inside the Pores of Reactive Electrochemical Membranes in the Process of the Anodic Oxidation of Organic Compounds." International Journal of Molecular Sciences 22, no. 11 (May 22, 2021): 5477. http://dx.doi.org/10.3390/ijms22115477.
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The use of reactive electrochemical membranes (REM) in flow-through mode during the anodic oxidation of organic compounds makes it possible to overcome the limitations of plate anodes: in the case of REM, the area of the electrochemically active surface is several orders of magnitude larger, and the delivery of organic compounds to the reaction zone is controlled by convective flow rather than diffusion. The main problem with REM is the formation of fouling and gas bubbles in the pores, which leads to a decrease in the efficiency of the process because the hydraulic resistance increases and the electrochemically active surface is shielded. This work aims to study the processes underlying the reduction in the efficiency of anodic oxidation, and in particular the formation of gas bubbles and the recharge of the REM pore surface at a current density exceeding the limiting kinetic value. We propose a simple one-dimensional non-stationary model of the transport of diluted species during the anodic oxidation of paracetamol using REM to describe the above effects. The processing of the experimental data was carried out. It was found that the absolute value of the zeta potential of the pore surface decreases with time, which leads to a decrease in the permeate flux due to a reduction in the electroosmotic flow. It was shown that in the solution that does not contain organic components, gas bubbles form faster and occupy a larger pore fraction than in the case of the presence of paracetamol; with an increase in the paracetamol concentration, the gas fraction decreases. This behavior is due to a decrease in the generation of oxygen during the recombination reaction of the hydroxyl radicals, which are consumed in the oxidation reaction of the organic compounds. Because the presence of bubbles increases the hydraulic resistance, the residence time of paracetamol—and consequently its degradation degree—increases, but the productivity goes down. The model has predictive power and, after simple calibration, can be used to predict the performance of REM anodic oxidation systems.
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Tsymbal, Sergey A., Anna A. Moiseeva, Nikol A. Agadzhanian, Svetlana S. Efimova, Alina A. Markova, Dmitry A. Guk, Olga O. Krasnovskaya, et al. "Copper-Containing Nanoparticles and Organic Complexes: Metal Reduction Triggers Rapid Cell Death via Oxidative Burst." International Journal of Molecular Sciences 22, no. 20 (October 14, 2021): 11065. http://dx.doi.org/10.3390/ijms222011065.
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Copper-containing agents are promising antitumor pharmaceuticals due to the ability of the metal ion to react with biomolecules. In the current study, we demonstrate that inorganic Cu2+ in the form of oxide nanoparticles (NPs) or salts, as well as Cu ions in the context of organic complexes (oxidation states +1, +1.5 and +2), acquire significant cytotoxic potency (2–3 orders of magnitude determined by IC50 values) in combinations with N-acetylcysteine (NAC), cysteine, or ascorbate. In contrast, other divalent cations (Zn, Fe, Mo, and Co) evoked no cytotoxicity with these combinations. CuO NPs (0.1–1 µg/mL) together with 1 mM NAC triggered the formation of reactive oxygen species (ROS) within 2–6 h concomitantly with perturbation of the plasma membrane and caspase-independent cell death. Furthermore, NAC potently sensitized HCT116 colon carcinoma cells to Cu–organic complexes in which the metal ion coordinated with 5-(2-pyridylmethylene)-2-methylthio-imidazol-4-one or was present in the coordination sphere of the porphyrin macrocycle. The sensitization effect was detectable in a panel of mammalian tumor cell lines including the sublines with the determinants of chemotherapeutic drug resistance. The components of the combination were non-toxic if added separately. Electrochemical studies revealed that Cu cations underwent a stepwise reduction in the presence of NAC or ascorbate. This mechanism explains differential efficacy of individual Cu–organic compounds in cell sensitization depending on the availability of Cu ions for reduction. In the presence of oxygen, Cu+1 complexes can generate a superoxide anion in a Fenton-like reaction Cu+1L + O2 → O2−. + Cu+2L, where L is the organic ligand. Studies on artificial lipid membranes showed that NAC interacted with negatively charged phospholipids, an effect that can facilitate the penetration of CuO NPs across the membranes. Thus, electrochemical modification of Cu ions and subsequent ROS generation, as well as direct interaction with membranes, represent the mechanisms of irreversible membrane damage and cell death in response to metal reduction in inorganic and organic Cu-containing compounds.
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Skolotneva, Ekaterina, Clement Trellu, Marc Cretin, and Semyon Mareev. "A 2D Convection-Diffusion Model of Anodic Oxidation of Organic Compounds Mediated by Hydroxyl Radicals Using Porous Reactive Electrochemical Membrane." Membranes 10, no. 5 (May 16, 2020): 102. http://dx.doi.org/10.3390/membranes10050102.
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In recent years, electrochemical methods utilizing reactive electrochemical membranes (REM) have been considered as a promising technology for efficient degradation and mineralization of organic compounds in natural, industrial and municipal wastewaters. In this paper, we propose a two-dimensional (2D) convection-diffusion-reaction model concerning the transport and reaction of organic species with hydroxyl radicals generated at a TiOx REM operated in flow-through mode. It allows the determination of unknown parameters of the system by treatment of experimental data and predicts the behavior of the electrolysis setup. There is a good agreement in the calculated and experimental degradation rate of a model pollutant at different permeate fluxes and current densities. The model also provides an understanding of the current density distribution over an electrically heterogeneous surface and its effect on the distribution profile of hydroxyl radicals and diluted species. It was shown that the percentage of the removal of paracetamol increases with decreasing the pore radius and/or increasing the porosity. The effect becomes more pronounced as the current density increases. The model highlights how convection, diffusion and reaction limitations have to be taken into consideration for understanding the effectiveness of the process.
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Pei, Shuzhao, Yi Wang, Shijie You, Zhanguo Li, and Nanqi Ren. "Electrochemical Removal of Chlorophenol Pollutants by Reactive Electrode Membranes: Scale-Up Strategy for Engineered Applications." Engineering 9 (February 2022): 77–84. http://dx.doi.org/10.1016/j.eng.2021.11.017.
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Wanzenberg, E., F. Tietz, L. G. J. de Haart, D. Kek, P. Panjan, and D. Stöver. "Reactive sputtering deposition and electrochemical characterisation of thin solid electrolyte membranes for solid oxide fuel cells." Ionics 8, no. 1-2 (January 2002): 142–48. http://dx.doi.org/10.1007/bf02377765.
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Reisert, Michael, Ashish Aphale, and Prabhakar Singh. "Solid Oxide Electrochemical Systems: Material Degradation Processes and Novel Mitigation Approaches." Materials 11, no. 11 (November 2, 2018): 2169. http://dx.doi.org/10.3390/ma11112169.
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Solid oxide electrochemical systems, such as solid oxide fuel cells (SOFC), solid oxide electrolysis cells (SOEC), and oxygen transport membranes (OTM) enable clean and reliable production of energy or fuel for a range of applications, including, but not limited to, residential, commercial, industrial, and grid-support. These systems utilize solid-state ceramic oxides which offer enhanced stability, fuel flexibility, and high energy conversion efficiency throughout operation. However, the nature of system conditions, such as high temperatures, complex redox atmosphere, and presence of volatile reactive species become taxing on solid oxide materials and limit their viability during long-term operation. Ongoing research efforts to identify the material corrosion and degradation phenomena, as well as discover possible mitigation techniques to extend material efficiency and longevity, is the current focus of the research and industrial community. In this review, degradation processes in select solid oxide electrochemical systems, system components, and comprising materials will be discussed. Overall degradation phenomena are presented and certain degradation mechanisms are discussed. State-of-the-art technologies to mitigate or minimize the above-mentioned degradation processes are presented.
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Prabhakaran, Venkateshkumar, Grant E. Johnson, Bingbing Wang, and Julia Laskin. "In situ solid-state electrochemistry of mass-selected ions at well-defined electrode–electrolyte interfaces." Proceedings of the National Academy of Sciences 113, no. 47 (November 7, 2016): 13324–29. http://dx.doi.org/10.1073/pnas.1608730113.
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Molecular-level understanding of electrochemical processes occurring at electrode–electrolyte interfaces (EEIs) is key to the rational development of high-performance and sustainable electrochemical technologies. This article reports the development and application of solid-state in situ thin-film electrochemical cells to explore redox and catalytic processes occurring at well-defined EEIs generated using soft-landing (SL) of mass- and charge-selected cluster ions. In situ cells with excellent mass-transfer properties are fabricated using carefully designed nanoporous ionic liquid membranes. SL enables deposition of pure active species that are not obtainable with other techniques onto electrode surfaces with precise control over charge state, composition, and kinetic energy. SL is, therefore, demonstrated to be a unique tool for studying fundamental processes occurring at EEIs. Using an aprotic cell, the effect of charge state (PMo12O403-/2-) and the contribution of building blocks of Keggin polyoxometalate (POM) clusters to redox processes are characterized by populating EEIs with POM anions generated by electrospray ionization and gas-phase dissociation. Additionally, a proton-conducting cell has been developed to characterize the oxygen reduction activity of bare Pt clusters (Pt30 ∼1 nm diameter), thus demonstrating the capability of the cell for probing catalytic reactions in controlled gaseous environments. By combining the developed in situ electrochemical cell with ion SL we established a versatile method to characterize the EEI in solid-state redox systems and reactive electrochemistry at precisely defined conditions. This capability will advance the molecular-level understanding of processes occurring at EEIs that are critical to many energy-related technologies.
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Yun, JaeHyoung, Seon Il Kim, and Wonhyoung Ryu. "Biomimetic Supported Lipid Bilayer on Thylakoid Membrane-Based Photobioelectrochemical System for Stability Enhancement." ECS Meeting Abstracts MA2022-01, no. 45 (July 7, 2022): 1888. http://dx.doi.org/10.1149/ma2022-01451888mtgabs.
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Light-induced charge separation in photosynthetic reaction centers has a very high quantum yield. Due to this high quantum yield, bioenergy harvesting using photosynthesis of plant has been studied extensively. In the studies using algal cells or chloroplasts, their lipid membranes interfere with electron extraction. Therefore, most of studies are underway by using extracted photosynthetic organelles such as photosystems (PS I, II) and thylakoid membranes (TMs). However, without lipid membrane, the stability of photosynthetic organelles cannot be maintained. This is because photosynthesis generates reactive oxygen species (ROS) and protons that cause the degradation of photosynthetic organelles along with the production of high-energy electrons. On the other hand, chloroplasts have the internal environment separated by the lipid membrane to maintain homeostasis, which controls the level of ROS and pH within the chloroplasts. In this study, by mimicking chloroplast, we propose to form a biomimetic supported lipid bilayer (SLB) to maintain stability while constructing a TM-based photobioelectrochemical system. Alginate was used as a synthetic extracellular matrix (ECM), and SLB was formed with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) through vesicle fusion. The swelling of the alginate prevents direct contact of TM-alginate composite film with the electrode and prevents separation of inside of the biomimetic protochloroplast from outside environment. To solve this problem, crosslink alginate with CaCl2 water solutions containing 20% ethanol to prevent warping of composite film and amino groups were created through silanization on ITO electrode to improve adhesion with film. Thereafter, SLB formation conditions were analyzed through confocal microscopy. With the formed DOPC SLB, it was verified by the dye release test whether the inside of protochloroplast was separated from the outside environment. Under the SLB-encapsulating environment, pH and ROS were controlled by ADP, ascorbate and glutathione. To confirm the improvement of the stability of TM, the long-term photocurrent was measured in the presence or absence of SLB and stability-maintaining materials. Moreover, SLB can act as a separator in electrochemical circuits due to its high electrical resistance. Electrical insulation property of SLB was confirmed using electrochemical impedance spectroscopy (EIS). References [1] Kosumi, Daisuke, et al. Journal of Photochemistry and Photobiology A: Chemistry 358 (2018): 374-378. [2] Pankratov, Dmitry, Galina Pankratova, and Lo Gorton. Current Opinion in Electrochemistry 19 (2020): 49-54. [3] Kluzek, Monika, et al. Soft matter 14.28 (2018): 5800-5810. [4] Blokhina, Olga, Eija Virolainen, and Kurt V. Fagerstedt. Annals of botany 91.2 (2003): 179-194. [5] Vockenroth, Inga K., et al. Biointerphases 3.2 (2008): FA68-FA73.
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Lin, Hui, Hanjun Peng, Xingwei Feng, Xiaojing Li, Jinbo Zhao, Kui Yang, Jianbo Liao, et al. "Energy-efficient for advanced oxidation of bio-treated landfill leachate effluent by reactive electrochemical membranes (REMs): Laboratory and pilot scale studies." Water Research 190 (February 2021): 116790. http://dx.doi.org/10.1016/j.watres.2020.116790.
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TARNG, DER-CHERNG, TZUNG-JIUN TSAI, WEI-TING CHEN, TSUNG-YUN LIU, and YAU-HUEI WEI. "Effect of HumanOGG11245C→G Gene Polymorphism on 8-Hydroxy-2′-Deoxyguanosine Levels of Leukocyte DNA among Patients Undergoing Chronic Hemodialysis." Journal of the American Society of Nephrology 12, no. 11 (November 2001): 2338–47. http://dx.doi.org/10.1681/asn.v12112338.
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Abstract. The effects of the humanOGG1gene (hOGG1) 1245C→G polymorphism on the 8-hydroxy-2′-deoxyguanosine (8-OHdG) contents of peripheral leukocyte DNA were investigated among chronic hemodialysis patients. First, thehOGG11245C→G transversion was assessed, by using a PCR-restriction fragment length polymorphism method, among 210 hemodialysis patients and 156 healthy individuals. Second, the 8-OHdG contents in leukocyte DNA were measured, by using an HPLC-electrochemical detection method, for 112 hemodialysis patients and 112 age-, gender-, and genotype-matched healthy control subjects. The three genotypes (as dummy variables) and age, gender, dialysis duration, dialyzer membrane type, blood antioxidant levels, and iron parameters were used as independent variables and the natural logarithm of the leukocyte 8-OHdG concentration was used as a dependent variable in a forward, stepwise, multiple-regression model. The results demonstrated that the allelic frequency ofhOGG11245G was 64.1% among 210 hemodialysis patients and 62.2% in the whole control population. The genotypic frequencies (CC/CG/GG ratio, 10%/51.9%/38.1%) for the hemodialysis patients did not differ significantly from those (16.7%/42.3%/41.0%) for the control subjects (P> 0.05,χ2test). The mean leukocyte 8-OHdG levels for the patients were significantly higher than those for the healthy control subjects (P< 0.001). Leukocyte 8-OHdG levels were further increased among patients with the 1245GG genotype, compared with patients with the 1245CG or CC genotype (P< 0.001, ANOVA), but levels were similar among healthy control subjects irrespective of thehOGG1gene polymorphism. It was also observed that patients who underwent dialysis with cellulose membranes exhibited significantly higher leukocyte 8-OHdG levels than did patients who underwent dialysis with polymethylmethacrylate, polysulfone, or vitamin E-bonded membranes (P< 0.001, ANOVA). The multivariate regression analysis revealed thathOGG11245C→G polymorphism and dialysis membrane type were the two independent predictors of 8-OHdG contents in leukocyte DNA from hemodialysis patients. This study demonstrated that the extent of oxidative DNA damage among chronic hemodialysis patients not only is influenced by overproduction of reactive oxygen species resulting from leukocyte contacts with complement-activating membranes and by impaired antioxidant defense mechanisms but also is genetically determined.
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Andrés, Celia María Curieses, José Manuel Pérez de la Lastra, Celia Andrés Juan, Francisco J. Plou, and Eduardo Pérez-Lebeña. "Chlorine Dioxide: Friend or Foe for Cell Biomolecules?A Chemical Approach." International Journal of Molecular Sciences 23, no. 24 (December 10, 2022): 15660. http://dx.doi.org/10.3390/ijms232415660.
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This review examines the role of chlorine dioxide (ClO2) on inorganic compounds and cell biomolecules. As a disinfectant also present in drinking water, ClO2 helps to destroy bacteria, viruses, and some parasites. The Environmental Protection Agency EPA regulates the maximum concentration of chlorine dioxide in drinking water to be no more than 0.8 ppm. In any case, human consumption must be strictly regulated since, given its highly reactive nature, it can react with and oxidize many of the inorganic compounds found in natural waters. Simultaneously, chlorine dioxide reacts with natural organic matter in water, including humic and fulvic acids, forming oxidized organic compounds such as aldehydes and carboxylic acids, and rapidly oxidizes phenolic compounds, amines, amino acids, peptides, and proteins, as well as the nicotinamide adenine dinucleotide NADH, responsible for electron and proton exchange and energy production in all cells. The influence of ClO2 on biomolecules is derived from its interference with redox processes, modifying the electrochemical balances in mitochondrial and cell membranes. This discourages its use on an individual basis and without specialized monitoring by health professionals.
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Kim, Sung Won, Young Hun Cho, Dahye Kim, and Seung Joon Yoo. "Understanding the Electrolyte/Electrode Interfacial Interactions for the Development of High-Performance Aqueous Redox-Enhanced Electrochemical Capacitors." ECS Meeting Abstracts MA2022-01, no. 1 (July 7, 2022): 4. http://dx.doi.org/10.1149/ma2022-0114mtgabs.
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Research in electrochemical energy storage is converging to target systems with battery-level energy density, and capacitor-level cycling stability and power density. One approach is to utilize redox-active electrolytes that add faradaic charge storage to increase energy density of supercapacitors. Aqueous redox-active electrolytes are simple to prepare and to up-scale; and, can be synergistically optimized to fully utilize the dynamic charge/discharge and storage properties of micro/mesoporous carbon based electrode systems. However, aqueous redox-enhanced electrochemical capacitors (redox ECs) have performed relatively poorly, primarily due to the cross-diffusion of soluble redox couples, reduced cycle life, and low operating voltages. In this presentation, we show that these challenges can be met by the use of liquid-to-solid phase transitions of redox electrolyte molecules, and their reversible confinement in the pores ( > 2 nm) of high-surface-area electrodes. This approach is demonstrated by the use of bromide catholyte and modified hydrophobic cations (e.g., viologens and tetrabutylammonium) that together induce reversible solid-state complexation of Br2/Br3 –. This mechanism solves the cross-diffusion issue of redox ECs without using costly ion-selective membranes, and has the added benefit of stabilizing the reactive bromine generated during charging. Using the concepts learned from this 1st generation configuration, we further developed high-performance aqueous-based redox ECs by (1) synthesizing differently functionalized/substituted viologen molecules and (2) optimizing the interfacial interactions between the viologens and hierarchically porous-structured carbon electrodes. In the second part of this presentation, we show systematic approaches to explore optimal parameters to improve the energy storage capacity of the device.
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Cecchetti, Marco, Thomas Allen Ebaugh, Francesco Toja, Leonard J. Bonville, Radenka Maric, Andrea Casalegno, and Matteo Zago. "Development of an Additional Selective Layer to Mitigate Crossover in Vanadium Redox Flow Batteries: Influence of Composition on Efficiency and Capacity Decay." ECS Meeting Abstracts MA2022-01, no. 3 (July 7, 2022): 467. http://dx.doi.org/10.1149/ma2022-013467mtgabs.
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Vanadium redox flow battery (VRFB) is a promising technology for energy storage because of its independent energy to power ratio and long cycle life. However, VRFB commercialization is still hindered by some technological issues, among which the capacity loss induced by the undesired transport of ions across the ion-exchange membrane. Depending on the nominal operating condition, the choice of a suitable membrane for VRFB application results from the trade-off between low vanadium ions permeability and high proton conductivity. Usually, in order to reduce undesired ion fluxes between the two half-cell electrolytes, the membrane thickness is relatively high, implying increased ohmic losses (i.e., reduced energy efficiency) and system capital cost. In fact, state of the art membranes can represent up to 50% of stack capital cost [1]. Nafion® is widely used due to its high conductivity, but it is not ideally selective towards vanadium ions, leading to the adoption of thicker membrane to limit capacity loss. Alternative cation exchange membranes like SPEEK or SPI are promising because of their reduced permeability, but the low conductivity limits system power density. Instead, anion exchange membranes are still limited by the poor chemical stability and low conductivity [2]. In a recent work [3], the authors demonstrated the proof of concept of an additional selective layer to mitigate vanadium crossover. The selective layer, termed as barrier, is a porous component in which pores size, tortuous path, thickness and composition are designed to improve ion/proton selectivity. The proof of concept was manufactured with reactive spray deposition technology (RSDT), which is a flame-based synthesis process unique to Dr. Radenka Maric’s research group. For the fabrication of the proof of concept, carbon-rich particles ∼4-10 nm in diameter were formed in the RSDT flame and were deposited directly onto Nafion® 212 (50 μm thick) simultaneously with a mixture of 1100EW Nafion® and Vulcan® XC-72R (∼40 nm diameter) that was sprayed from air-assisted secondary nozzles. The presence of the barrier layer significantly reduced battery self-discharge, as reported in [3]. In this work, different compositions and morphologies of the barrier layers were analysed in order to improve ion/proton selectivity. In particular, the influence of ionomer to carbon ratio (I/C), the amount of carbon-rich particles and the introduction of silica were investigated. Moreover, the effect of Nafion® 211 (25 μm thick) as a support for barrier deposition was also evaluated. The barrier layers were characterized in a 25 cm2 cell [4] equipped with reference electrodes at both positive and negative electrode in order to monitor the corresponding electrolyte potential and get an insight into battery state of charge (SoC). In addition to electrochemical testing, the structure of the barrier layer was characterized using TEM and SEM. The most suitable I/C ratio was found to be included between 1 and 2, while the presence of carbon-rich particles significantly contributed to crossover reduction, with a minor impact on proton conductivity. Also the introduction of silica nanoparticles from primary nozzle was effective for vanadium ion selectivity, in particular when the amount of carbon from the secondary nozzle is reduced. In fact, the most promising barrier layer resulted the one composed by only silica and ionomer. This layer was also deposited on Nafion® 211 (Figure 1), exhibiting an excellent trade-off between ion selectivity and proton conductivity. This barrier was proved to be stable over 1,000 cycles, presenting a stable coulombic efficiency of 99.5%, with an average capacity decay of 0.08%/cycle at 100 mA cm-2. Figure 1 – SEM image of only Silica barrier deposited on Nafion® 211. References: [1] C. Minke et al., Journal of Power Sources 376 (2018) 66-81. [2] Y. Shi et al., Applied Energy 238 (2019) 202-224. [3] M. Cecchetti et al., Journal of the Electrochemical Society 167 (2020) 130535. [4] M. Cecchetti et al., Journal of Power Sources 400 (2018) 218-224. Figure 1
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Shnaiter, Marwah, John Graves, Anna Bogush, and Rong Lan. "(Digital Presentation) Fabrication and Electrochemical Characterization of Inkjet Printed IrO2 Electrodes for Water Electrolysis." ECS Meeting Abstracts MA2022-01, no. 41 (July 7, 2022): 2512. http://dx.doi.org/10.1149/ma2022-01412512mtgabs.
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Water electrolysis is believed to be one of the most promising technologies to produce green hydrogen. However, the current challenge in commercialising this technology is the high relative cost. According to a recent report on cost breakdown of Polymer Electrolyte Membrane (PEM) electrolyser [1], the cell stack contributes to 35% - 45% of the total cost. Catalyst materials on the electrodes are believed to be the primary areas for innovation and cost reduction in PEM electrolysers. Several approaches have been applied to reduce the stack cost, with a focus on reducing material usage while enhancing the performance of PEM electrolysers. This project aims to reduce catalyst loading on the anode of PEM water electrolyser while maintaining high performance, through developing an inkjet printing technique to create a thin, porous and active catalyst layer. Conventional catalyst fabrication techniques such as spray coating produce large amount of material waste and non-homogenous distribution on the surface [2]. Inkjet printing will provide controlled catalyst loading, ensuring well catalyst distribution, creating porous structure, and having the ability to create patterned electrodes [3]. Due to its high activity, Iridium Oxide (IrO2) is selected as the catalyst. The ink was formulated to be compatible with the printing requirement, with 7.5 wt% of IrO2 powder, 7.9 wt% of Nafion, and 84.5 wt% of solvents mixture of Isopropanol and Propylene Glycol. Full coverage of the catalyst on the Titanium substrate was proven by Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX). The effect on varying the number of printed layers was analysed in terms of catalyst loading and activity to show a linear increase in activity with the number of layers. Moreover, electrochemical performance was inspected using cyclic voltammetry in a 3-electrodes cell. The printed electrodes showed comparable stability to conventional electrodes. Electrochemical surface area (ECSA) was higher for the 10-layered electrodes as compared to the 2-layered electrodes indicating higher catalyst utilisation. Printed electrodes showed activity of 300 mA/mg IrO2 with ECSA of 225 cm2 at reduced catalyst loading of 0.8 mg IrO2/cm2. These results outperform conventionally fabricated electrodes by spray and decal transfer coatings [4]. References [1] A. T. Mayyas, M. F. Ruth, B. S. Pivovar, G. Bender, and K. B. Wipke, “Manufacturing Cost Analysis for Proton Exchange Membrane Water Electrolyzers,” NREL/TP-6A20-72740, 1557965, Aug. 2019. doi: 10.2172/1557965. [2] W. Qing, F. Liu, H. Yao, S. Sun, C. Chen, and W. Zhang, “Functional catalytic membrane development: A review of catalyst coating techniques,” Adv. Colloid Interface Sci., vol. 282, p. 102207, Aug. 2020, doi: 10.1016/j.cis.2020.102207. [3] J.-J. Chen, G.-Q. Lin, Y. Wang, E. Sowade, R. R. Baumann, and Z.-S. Feng, “Fabrication of conductive copper patterns using reactive inkjet printing followed by two-step electroless plating,” Appl. Surf. Sci., vol. 396, pp. 202–207, Feb. 2017, doi: 10.1016/j.apsusc.2016.09.152. [4] Z. Xie et al., “Optimization of catalyst-coated membranes for enhancing performance in proton exchange membrane electrolyzer cells,” Int. J. Hydrog. Energy, vol. 46, no. 1, pp. 1155–1162, Jan. 2021, doi: 10.1016/j.ijhydene.2020.09.239.
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Hasa, Bjorn. "Tuning the Selectivity of Liquid Products during CO Electroreduction." ECS Meeting Abstracts MA2022-02, no. 50 (October 9, 2022): 2508. http://dx.doi.org/10.1149/ma2022-02502508mtgabs.
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The electrochemical carbon dioxide reduction (eCO2RR) into value-added chemicals and fuels offers a sustainable route to close the anthropogenic carbon cycle and store the renewable sources' excess energy into chemical bonds. Typically, eCO2RR/eCORR studies employ reactant reduction in the cathode and oxygen evolution reaction in the anode. The membrane (membrane electrode assembly configuration) facilitates the ion transport between the two electrodes and chemically isolate the occurring electrochemical half-reactions. It should be noted that investigators have conceptualized the use of ion-exchange membranes in order to improve the reaction energy efficiency and rate. However, the impact of membrane properties on reaction selectivity, stability, and efficiency remains unexplored. Herein, we investigated the role of anion exchange membrane on the CO reduction performance using a membrane electrode assembly configuration. This talk will provide insights into the ion-exchange membrane's role in the electrocatalytic reduction of CO. We will show how the membrane properties determine the product crossover, product selectivity, and stability. For example, we will discuss: i) the impact of membrane thickness on the product crossover and applied potential, ii) the role of the membrane on the cell stability, iii) the possibility of various membrane functional groups to tune the reaction selectivity and stability, and iv) the role of counter-ion, ion exchange capacity (IEC), and membrane reinforcement on the cell performance. This work will provide a first step toward designing an ion-exchange membrane with the desired characteristics for CO electroreduction.
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Wu, Aston J., Benjamin C. K. Tong, Alexis S. Huang, Min Li, and King-Ho Cheung. "Mitochondrial Calcium Signaling as a Therapeutic Target for Alzheimer’s Disease." Current Alzheimer Research 17, no. 4 (June 29, 2020): 329–43. http://dx.doi.org/10.2174/1567205016666191210091302.
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Mitochondria absorb calcium (Ca2+) at the expense of the electrochemical gradient generated during respiration. The influx of Ca2+ into the mitochondrial matrix helps maintain metabolic function and results in increased cytosolic Ca2+ during intracellular Ca2+ signaling. Mitochondrial Ca2+ homeostasis is tightly regulated by proteins located in the inner and outer mitochondrial membranes and by the cross-talk with endoplasmic reticulum Ca2+ signals. Increasing evidence indicates that mitochondrial Ca2+ overload is a pathological phenotype associated with Alzheimer’s Disease (AD). As intracellular Ca2+ dysregulation can be observed before the appearance of typical pathological hallmarks of AD, it is believed that mitochondrial Ca2+ overload may also play an important role in AD etiology. The high mitochondrial Ca2+ uptake can easily compromise neuronal functions and exacerbate AD progression by impairing mitochondrial respiration, increasing reactive oxygen species formation and inducing apoptosis. Additionally, mitochondrial Ca2+ overload can damage mitochondrial recycling via mitophagy. This review will discuss the molecular players involved in mitochondrial Ca2+ dysregulation and the pharmacotherapies that target this dysregulation. As most of the current AD therapeutics are based on amyloidopathy, tauopathy, and the cholinergic hypothesis, they achieve only symptomatic relief. Thus, determining how to reestablish mitochondrial Ca2+ homeostasis may aid in the development of novel AD therapeutic interventions.
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Yang, Kui, Xingwei Feng, Hui Lin, Jiale Xu, Cao Yang, Juan Du, Dengmiao Cheng, Sihao Lv, and Zhifeng Yang. "Insight into the rapid elimination of low-concentration antibiotics from natural waters using tandem multilevel reactive electrochemical membranes: Role of direct electron transfer and hydroxyl radical oxidation." Journal of Hazardous Materials 423 (February 2022): 127239. http://dx.doi.org/10.1016/j.jhazmat.2021.127239.
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Ketmen, Simge, Simge Er Zeybekler, Sultan Sacide Gelen, and Dilek Odaci. "Graphene Oxide-Magnetic Nanoparticles Loaded Polystyrene-Polydopamine Electrospun Nanofibers Based Nanocomposites for Immunosensing Application of C-Reactive Protein." Biosensors 12, no. 12 (December 16, 2022): 1175. http://dx.doi.org/10.3390/bios12121175.
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The large surface area/volume ratio and controllable surface conformation of electrospun nanofibers (ENFs) make them highly attractive in applications where a large surface area is desired, such as sensors and affinity membranes. In this study, nanocomposite-based ENFs were produced and immobilization of Anti-CRP was carried out for the non-invasive detection of C-reactive protein (CRP). Initially, the synthesis of graphene oxide (GO) was carried out and it was modified with magnetic nanoparticles (MNP, Fe3O4) and polydopamine (PDA). Catechol-containing and quinone-containing functional groups were created on the nanocomposite surface for the immobilization of Anti-CRP. Polystyrene (PS) solution was mixed with rGO-MNP-PDA nanocomposite and PS/rGO-MNP-PDA ENFs were produced with bead-free, smooth, and uniform. The surface of the screen-printed carbon electrode (SPCE) was covered with PS/rGO-MNP-PDA ENFs by using the electrospinning technique under the determined optimum conditions. Next, Anti-CRP immobilization was carried out and the biofunctional surface was created on the PS/rGO-MNP-PDA ENFs coated SPCE. Moreover, PS/rGO-PDA/Anti-CRP and PS/MNP-PDA/Anti-CRP immunosensors were also prepared and the effect of each component in the nanocomposite-based electrospun nanofiber (MNP, rGO) on the sensor response was investigated. The analytic performance of the developed PS/rGO-MNP-PDA/Anti-CRP, PS/rGO-PDA/Anti-CRP, and PS/MNP-PDA/Anti-CRP immunosensors were examined by performing electrochemical measurements in the presence of CRP. The linear detection range of PS/rGO-MNP-PDA/Anti-CRP immunosensor was found to be from 0.5 to 60 ng/mL and the limit of detection (LOD) was calculated as 0.33 ng/mL for CRP. The PS/rGO-MNP-PDA/Anti-CRP immunosensor also exhibited good repeatability with a low coefficient of variation.
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Ramirez-Nava, Jonathan, Mariana Martínez-Castrejón, Rocío Lley García-Mesino, Jazmin Alaide López-Díaz, Oscar Talavera-Mendoza, Alicia Sarmiento-Villagrana, Fernando Rojano, and Giovanni Hernández-Flores. "The Implications of Membranes Used as Separators in Microbial Fuel Cells." Membranes 11, no. 10 (September 28, 2021): 738. http://dx.doi.org/10.3390/membranes11100738.
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Microbial fuel cells (MFCs) are electrochemical devices focused on bioenergy generation and organic matter removal carried out by microorganisms under anoxic environments. In these types of systems, the anodic oxidation reaction is catalyzed by anaerobic microorganisms, while the cathodic reduction reaction can be carried out biotically or abiotically. Membranes as separators in MFCs are the primary requirements for optimal electrochemical and microbiological performance. MFC configuration and operation are similar to those of proton-exchange membrane fuel cells (PEMFCs)—both having at least one anode and one cathode split by a membrane or separator. The Nafion® 117 (NF-117) membrane, made from perfluorosulfonic acid, is a membrane used as a separator in PEMFCs. By analogy of the operation between electrochemical systems and MFCs, NF-117 membranes have been widely used as separators in MFCs. The main disadvantage of this type of membrane is its high cost; membranes in MFCs can represent up to 60% of the MFC’s total cost. This is one of the challenges in scaling up MFCs: finding alternative membranes or separators with low cost and good electrochemical characteristics. The aim of this work is to critically review state-of-the-art membranes and separators used in MFCs. The scope of this review includes: (i) membrane functions in MFCs, (ii) most-used membranes, (iii) membrane cost and efficiency, and (iv) membrane-less MFCs. Currently, there are at least 20 different membranes or separators proposed and evaluated for MFCs, from basic salt bridges to advanced synthetic polymer-based membranes, including ceramic and unconventional separator materials. Studies focusing on either low cost or the use of natural polymers for proton-exchange membranes (PEM) are still scarce. Alternatively, in some works, MFCs have been operated without membranes; however, significant decrements in Coulombic efficiency were found. As the type of membrane affects the performance and total cost of MFCs, it is recommended that research efforts are increased in order to develop new, more economic membranes that exhibit favorable properties and allow for satisfactory cell performance at the same time. The current state of the art of membranes for MFCs addressed in this review will undoubtedly serve as a key insight for future research related to this topic.
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Kim, Ae, and Dong Yoo. "A Comparative Study on Physiochemical, Thermomechanical, and Electrochemical Properties of Sulfonated Poly(Ether Ether Ketone) Block Copolymer Membranes with and without Fe3O4 Nanoparticles." Polymers 11, no. 3 (March 21, 2019): 536. http://dx.doi.org/10.3390/polym11030536.
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The composite structure, good porosity, and electrochemical behavior of proton exchange membranes (PEMs) are important characteristics, which can improve the performance of polymer electrolyte fuel cells (PEFCs). In this study, we designed and synthesized an XY block copolymer via a polycondensation reaction that contains sulfonated poly(ether ether ketone) (SPEEK) (X) as a hydrophilic unit and a fluorinated oligomer (Y) as a hydrophobic unit. The prepared XY block copolymer is composed of Fe3O4 nanoparticles to create composite architecture, which was subsequently treated with a 1 M H2SO4 solution at 70 °C for 1 h to eliminate Fe3O4 and generate a pores structure in the membrane. The morphological, physiochemical, thermomechanical, and electrochemical properties of bare XY, XY/Fe3O4-9 and XY(porous)-9 membranes were measured and compared in detail. Compared with XY/Fe3O4-9 composite, the proton conductivity of XY(porous)-9 membrane was remarkably enhanced as a result of the existence of pores as nano-conducting channels. Similarly, the XY(porous)-9 membrane exhibited enhanced water retention and ion exchange capacity among the prepared membranes. However, the PEFC power density of XY(porous)-9 membrane was still lower than that of XY/Fe3O4-9 membrane at 60 °C and 60% relative humidity. Also, the durability of XY(porous)-9 membrane is found to be lower compared with pristine XY and XY/Fe3O4-9 membranes as a result of the hydrogen crossover through the pores of the membrane.
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Pei, Shuzhao, Han Shi, Jinna Zhang, Shengli Wang, Nanqi Ren, and Shijie You. "Electrochemical removal of tetrabromobisphenol A by fluorine-doped titanium suboxide electrochemically reactive membrane." Journal of Hazardous Materials 419 (October 2021): 126434. http://dx.doi.org/10.1016/j.jhazmat.2021.126434.
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VORTMAN, M. YA, V. N. LEMESHKO, L. A. GONCHARENKO, S. M. KOBYLINSKIY, V. V. SHEVCHENKO, and S. N. OSTAPIUK. "OLIGOMERIC GUANIDINE-CONTAINING PROTON CATIONIC IONIC LIQUID." Polymer journal 43, no. 4 (November 26, 2021): 304–10. http://dx.doi.org/10.15407/polymerj.43.04.304.
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Oligomeric ionic liquids occupy an intermediate position between low molecular weight and polymeric. They are promising as polymer electrolytes in electrochemical devices for various purposes, membranes for the separation of gas mixtures, in sensor technologies, and so on. Oligomeric guanidinium ionic liquids are practically not described in the literature. In terms of studying the effect of the structure of the epoxy component on the properties of oligomeric ionic liquids of this type, it is advisable to introduce into its composition an aliphatic oligoether component. The choice of aliphatic oligoepoxide for the synthesis of guanidinium oligomeric ionic liquids is based on the fact that it is structurally similar to poly - and oligoethylene oxides, which are known to be non-toxic, biodegradable, and reactive oligomeric ionic liquids at elevated temperatures. A new type of reactive oligomeric proton cationic ionic liquid was synthesized by the reaction of oligomeric aliphatic diepoxide with guanidine, followed by neutralization of the product with hydrochloric acid. In this study, the synthesis of proton cationic oligomeric ionic liquids was based on the introduction of guanidinium fragments as end groups of the oligoether aliphatic chain. This reaction is attractive because of the ease of opening the oxirane ring with such a strong nucleophile as guanidine.The reaction forms a fragment with an aliphatic C-N bond, which retains the high basicity of the nitrogen atom. Its structure is characterized by the presence of guanidinium groups at the ends of the aliphatic hydroxyl-containing oligoether chain. The chemical structure of this compound is characterized by IR -, 1H ,13 C NMR spectroscopy methods, and its molecular mass characteristics are determined.The average molecular weight of the synthesized oligomeric ionic liquids is 610 g / mol.The value of the coefficient of polydispersity of the synthesized oligomeric ionic liquids is equal to 1.2. Determination of the content of amino groups in the guanidine-containing oligomer in the basic form by titrometric method allowed to establish that the value found is close to the theoretically calculated value. The synthesized oligomeric proton ionic liquid is characterized by an amorphous structure with two glass transition temperatures. The first lies in the range -70 °C, the second in the region of 70 °C, and the beginning of thermal oxidative destruction is located in the region of 148 °C. The temperature dependence of the ionic conductivity for this compound is nonlinear in the Arrhenius coordinates, which indicates the realization of ionic conductivity mainly due to the free volume in the system. The proton conductivity of this compound is 6.4·10-5–1·10-2Cm/cmin the range of 20–100 °C. The obtained compound exhibits surface-active properties characteristic of classical surfactants, as evidenced by the value of the limiting surface activity – 2.8·102 Nm2 / kmol. The value of CCM is 1.8·10-2 mol/l., and the value of the minimum surface tension – 37.70 mN / m. The synthesized oligomeric ionic liquid is of interest as electrolytes operating under anhydrous conditions, surfactants, disinfectants, and starting reagents for the synthesis of ion-containing blockopolymers.
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Zhao, Nana, Zhiqing Shi, Régis Chenitz, François Girard, and Asmae Mokrini. "Effects of 1, 2, 4-Triazole Additive on PEM Fuel Cell Conditioning." Membranes 10, no. 11 (October 22, 2020): 301. http://dx.doi.org/10.3390/membranes10110301.
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Melt processing is one of the essential technologies for the mass production of polymer electrolyte membranes (PEM) at low cost. Azoles have been widely used in PEM to improve their conductivity at a relatively low humidity and recently as bifunctional additives in a melt blowing processing for PEM mass production. In this work, we attempted to assess the effect of 1, 2, 4-triazole additive in membranes and in catalyst layers on PEM fuel cell conditioning. Various characterization tools including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and conditioning with constant current were applied to diagnose the temporary electrochemical reaction effect and the permanent performance loss caused by the triazole additives. It was found that triazole additives in membranes could migrate into the catalyst layers and significantly affect the open circuit voltage (OCV) and the conditioning. The effect could be partially or completely removed/cleaned either through longer conditioning time or via CV cycling, which depends on the amount of additives remaining in the membrane. The findings provide valuable scientific insights on the relevance of post treatment steps during membrane production and overcoming fuel cell contamination issues due to residual additive in the membranes and understanding the quality control needed for fuel cell membranes by melt blowing processing.
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Arslan, Funda, Khajidkhand Chuluunbandi, Anna Freiberg, Attila Kormanyos, Ferit Sit, Serhiy Cherevko, Jochen Alfred Kerres, Simon Thiele, and Thomas Böhm. "Quaternized Polybenzimidazole-Cross-Linked Poly(vinylbenzyl chloride) Membranes and Their Performance in HT-PEMFCs." ECS Meeting Abstracts MA2022-01, no. 35 (July 7, 2022): 1411. http://dx.doi.org/10.1149/ma2022-01351411mtgabs.
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Quaternized Polybenzimidazole-Cross-Linked Poly(vinylbenzyl chloride) Membranes and Their Performance in HT-PEMFCs Keywords: Proton-exchange membrane, ion pair, high-temperature, phosphoric acid, quaternary ammonium, hydrogen crossover High temperature proton-exchange membrane fuel cells (HT-PEMFCs) are promising electrochemical energy conversion devices for the hydrogen economy. In this fuel cell type, phosphoric acid is immobilized as an electrolyte within a polybenzimidazole (PBI) membrane acting as a matrix. These membrane systems allow operating temperatures up to 200 °C, which is significantly higher than for sulfonated polymers that are used in low temperatures PEMFCs at around 80 °C. Operating PEMFCs above 100 °C harbors advantages such as faster reaction kinetics, higher tolerances against fuel impurities, and easier cooling. Nonetheless, phosphoric acid doped membranes also is the main challenge and drawback of these systems due to leaching of the dopant over time. A high acid-oping level is desired since it ensures high proton conductivity. However, the mechanical properties of PBI-based materials generally deteriorate upon increasing acid doping levels. In this regard, cross-linking PBI with another polymer is a promising route to enhance the mechanical properties of acid-doped membranes. Further, polymers with specific functional groups, such as quaternary ammonium (QA), can be used as cross-linkers to enhance the retention of phosphoric acid by forming strong interactions with biphosphate anions. Here, we present a new ion-pair-coordinated membrane (IPM) system decorated with QA groups. Poly(vinylbenzyl chloride) is used as a macromolecular cross-linker for PBI, and three different amines (Quinuclidine, Quinuclidinol, DABCO) are used as quaternizing agents. The performance of these membranes is evaluated ex-situ as well as electrochemically within HT-PEMFC operation and compared to a commercial m-PBI membrane (Dapazol). The IPMs show reduced swelling and better mechanical properties upon doping. Further, the commercial reference can be outperformed within HT-PEMFC operation at less acid doping than conventional PBI membranes. The best-performing IPM led to a 25% improved fuel cell performance. The peak power density of an HT-PEMFC incorporating a Dapazol membrane was 430 mW cm–2 at 180 °C under H2/air conditions and at ambient pressure, while the HT-PEMFC with the best-performing IPM yielded 530 cm–2 at equal parameters. Further, the hydrogen gas crossover of the IPMs is similar or less than that of the commercial reference even at lower membrane thicknesses, which renders these membranes as promising candidates for application in HT-PEMFC.
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Huang, Edward, Townshend White, Beibei Wang, Huanhuan Shi, and Jiayang Liu. "Disinfection of Escherichia coli by a Reactive Electrochemical Membrane System Involving Activated Carbon Fiber Cloth (ACFC)." Water 11, no. 3 (February 28, 2019): 430. http://dx.doi.org/10.3390/w11030430.
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This study examined a novel reactive electrochemical membrane (REM) system with activated carbon fiber cloth (ACFC) serving simultaneously as the anode and the membrane to effectively disinfect water that was filtered through the device. An Escherichia coli strain was inoculated to water as a model pathogen. The influence of REM operation parameters, including the number of ACFC layers, voltage, flow rate and operation time, was evaluated. Up to 7.5 log unit reduction of E. coli concentration in water was achieved at the optimal treatment condition, while the energy consumption was 1.5 kWh/m3 per log unit reduction of E. coli. This makes it possible to use this ACFC-based REM technology for point-of-use water disinfection to provide clean water for underdeveloped regions. Further tests by free radical probing, Linear Scan Voltammetry (LSV) and Scanning Electron Microscopy (SEM) suggest that the disinfection involved the filtration/retention of bacteria on ACFC and attack by reactive oxygen species generated electrochemically on the anode.
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Zou, Xingli, Kai Zheng, Xionggang Lu, Qian Xu, and Zhongfu Zhou. "Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt." Faraday Discussions 190 (2016): 53–69. http://dx.doi.org/10.1039/c5fd00221d.
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Silicon carbide (SiC), titanium carbide (TiC), zirconium carbide (ZrC), and tantalum carbide (TaC) have been electrochemically produced directly from their corresponding stoichiometric metal oxides/carbon (MOx/C) precursors by electrodeoxidation in molten calcium chloride (CaCl2). An assembled yttria stabilized zirconia solid oxide membrane (SOM)-based anode was employed to control the electrodeoxidation process. The SOM-assisted controllable electrochemical process was carried out in molten CaCl2 at 1000 °C with a potential of 3.5 to 4.0 V. The reaction mechanism of the electrochemical production process and the characteristics of these produced metal carbides (MCs) were systematically investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses clearly identify that SiC, TiC, ZrC, and TaC carbides can be facilely fabricated. SiC carbide can be controlled to form a homogeneous nanowire structure, while the morphologies of TiC, ZrC, and TaC carbides exhibit porous nodular structures with micro/nanoscale particles. The complex chemical/electrochemical reaction processes including the compounding, electrodeoxidation, dissolution–electrodeposition, and in situ carbonization processes in molten CaCl2 are also discussed. The present results preliminarily demonstrate that the molten salt-based SOM-assisted electrodeoxidation process has the potential to be used for the facile and controllable electrodeoxidation of MOx/C precursors to micro/nanostructured MCs, which can potentially be used for various applications.
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Song, Hyeon-Bee, Do-Hyeong Kim, and Moon-Sung Kang. "Thin-Reinforced Anion-Exchange Membranes with High Ionic Contents for Electrochemical Energy Conversion Processes." Membranes 12, no. 2 (February 8, 2022): 196. http://dx.doi.org/10.3390/membranes12020196.
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Ion-exchange membranes (IEMs) are a core component that greatly affects the performance of electrochemical energy conversion processes such as reverse electrodialysis (RED) and all-vanadium redox flow battery (VRFB). The IEMs used in electrochemical energy conversion processes require low mass transfer resistance, high permselectivity, excellent durability, and also need to be inexpensive to manufacture. Therefore, in this study, thin-reinforced anion-exchange membranes with excellent physical and chemical stabilities were developed by filling a polyethylene porous substrate with functional monomers, and through in situ polymerization and post-treatments. In particular, the thin-reinforced membranes were made to have a high ion-exchange capacity and a limited degree of swelling at the same time through a double cross-linking reaction. The prepared membranes were shown to possess both strong tensile strength (>120 MPa) and low electrical resistance (<1 Ohm cm2). As a result of applying them to RED and VRFB, the performances were shown to be superior to those of the commercial membrane (AMX, Astom Corp., Japan) in the optimal composition. In addition, the prepared membranes were found to have high oxidation stability, enough for practical applications.
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Bae, Chulsung. "(Invited) Molecular Engineering of Ion-Conducting Polymer Membranes for Electrochemical Energy Storage and Conversion Technologies." ECS Meeting Abstracts MA2022-01, no. 39 (July 7, 2022): 1731. http://dx.doi.org/10.1149/ma2022-01391731mtgabs.
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Anion exchange membranes (AEMs) based on hydroxide-conducting polymers are a key component for anion-based electrochemical energy technology such as fuel cells, electrolyzers, and advanced batteries. Although these alkaline electrochemical technologies offer a promising alternative to acidic proton exchange membrane electrochemical devices, the access to chemically stable, mechanically durable, high-performing polymer electrolyte materials has been bottleneck to advance electrochemical technologies for hydrogen and other green chemicals until now. Despite vigorous research of AEM polymer design, examples of high-performance polymers with good alkaline stability at an elevated temperature are uncommon. Traditional aromatic polymers used in AEM applications contain a heteroatomic backbone linkage which is prone to degradation via nucleophilic attack by hydroxide ion. In this presentation, I will highlight recent progress at the Bae group of Rensselaer Polytechnic Institute in the development of advanced hydroxide-conducting polymers and membranes for AEM technology applications. We have developed a number of synthetic methodologies that produce polymer design made of all C−C bond backbones and a flexible chain-tethered quaternary ammonium group and that provide an effective solution to the problem of alkaline stability. The advantage of good solvent processability, synthetic versatility, and convenient scalability of the reaction process has generated considerable interest of these polymers, and they are considered leading candidates for commercial standard AEM. AEM fuel cells, electrolyzer, and redox flow battery tests of some of the developed polymer membranes showed excellent performance, suggesting that this new class of AEMs open a new avenue to electrochemical devices with real-world applications.
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Mo, Jingke, Zhenye Kang, Scott T. Retterer, David A. Cullen, Todd J. Toops, Johney B. Green, Matthew M. Mench, and Feng-Yuan Zhang. "Discovery of true electrochemical reactions for ultrahigh catalyst mass activity in water splitting." Science Advances 2, no. 11 (November 2016): e1600690. http://dx.doi.org/10.1126/sciadv.1600690.
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Better understanding of true electrochemical reaction behaviors in electrochemical energy devices has long been desired. It has been assumed so far that the reactions occur across the entire catalyst layer (CL), which is designed and fabricated uniformly with catalysts, conductors of protons and electrons, and pathways for reactants and products. By introducing a state-of-the-art characterization system, a thin, highly tunable liquid/gas diffusion layer (LGDL), and an innovative design of electrochemical proton exchange membrane electrolyzer cells (PEMECs), the electrochemical reactions on both microspatial and microtemporal scales are revealed for the first time. Surprisingly, reactions occur only on the CL adjacent to good electrical conductors. On the basis of these findings, new CL fabrications on the novel LGDLs exhibit more than 50 times higher mass activity than conventional catalyst-coated membranes in PEMECs. This discovery presents an opportunity to enhance the multiphase interfacial effects, maximizing the use of the catalysts and significantly reducing the cost of these devices.
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Jing, Yin, Lun Guo, and Brian P. Chaplin. "Electrochemical impedance spectroscopy study of membrane fouling and electrochemical regeneration at a sub-stoichiometric TiO2 reactive electrochemical membrane." Journal of Membrane Science 510 (July 2016): 510–23. http://dx.doi.org/10.1016/j.memsci.2016.03.029.
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Tellez-Cruz, Miriam M., Jorge Escorihuela, Omar Solorza-Feria, and Vicente Compañ. "Proton Exchange Membrane Fuel Cells (PEMFCs): Advances and Challenges." Polymers 13, no. 18 (September 10, 2021): 3064. http://dx.doi.org/10.3390/polym13183064.
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The study of the electrochemical catalyst conversion of renewable electricity and carbon oxides into chemical fuels attracts a great deal of attention by different researchers. The main role of this process is in mitigating the worldwide energy crisis through a closed technological carbon cycle, where chemical fuels, such as hydrogen, are stored and reconverted to electricity via electrochemical reaction processes in fuel cells. The scientific community focuses its efforts on the development of high-performance polymeric membranes together with nanomaterials with high catalytic activity and stability in order to reduce the platinum group metal applied as a cathode to build stacks of proton exchange membrane fuel cells (PEMFCs) to work at low and moderate temperatures. The design of new conductive membranes and nanoparticles (NPs) whose morphology directly affects their catalytic properties is of utmost importance. Nanoparticle morphologies, like cubes, octahedrons, icosahedrons, bipyramids, plates, and polyhedrons, among others, are widely studied for catalysis applications. The recent progress around the high catalytic activity has focused on the stabilizing agents and their potential impact on nanomaterial synthesis to induce changes in the morphology of NPs.
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Ran, Fen, Dan Li, and Jiayu Wu. "Constructing Functional Ionic Membrane Surface by Electrochemically Mediated Atom Transfer Radical Polymerization." International Journal of Polymer Science 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/3083716.
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The sodium polyacrylate (PAANa) contained polyethersulfone membrane that was fabricated by preparation of PES-NH2via nonsolvent phase separation method, the introduction of bromine groups as active sites by graftingα-Bromoisobutyryl bromide, and surface-initiated electrochemically atom transfer radical polymerization (SI-eATRP) of sodium acrylate (AANa) on the surface of PES membrane. The polymerization could be controlled by reaction condition, such as monomer concentration, electric potential, polymerization time, and modifier concentration. The membrane surface was uniform when the monomer concentration was 0.9 mol/L, the electric potential was −0.12 V, the polymerization time was 8 h, and the modifier concentration was 2 wt.%. The membrane showed excellent hydrophilicity and blood compatibility. The water contact angle decreased from 84° to 68° and activated partial thromboplastin increased from 51 s to 84 s after modification of the membranes.
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Zhang, Jie, Qilong Gan, Xianzhi Yuan, Zhipeng Xiang, Zhiyong Fu, and Zhenxing Liang. "Elucidating Spatial Distribution of Electrochemical Reaction in a Porous Electrode by Electrochemical Impedance Spectra for Flow Batteries." Batteries 9, no. 1 (December 26, 2022): 17. http://dx.doi.org/10.3390/batteries9010017.
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A porous electrode is an essential component in a flow battery, and its structure determines the battery's performance. The coupling of the multi-temporal-spatial-scale processes (e.g., electrochemical reaction, mass transfer, charge transfer) makes the recognition of each process complicated. Herein, a symmetric flow cell device is developed, and the electrochemical impedance measurement (two- or three-electrode configuration) is realized to elucidate the electrochemical processes. First, the effect of flow rate and concentration on the impedance spectra is investigated to identify the electrochemical processes. Second, the distributed resistance is quantified to describe the spatial distribution of the electrochemical reaction. It is found that the electrochemical reaction occurs near the membrane side at a low polarization current, and the reaction zones spatially extend from the membrane side to the current collector with the increase of imposed polarization. Such an evolution of the spatial distribution stems from the trade-off between the mass transfer and the ion conduction in the porous electrode. This work provides an experimental method to nondestructively probe the electrochemical processes, and the result provides guidance for developing innovative electrode structures for flow batteries.
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Ambrózy, Anton, Lenka Hlavatá, and Ján Labuda. "Protective membranes at electrochemical biosensors." Acta Chimica Slovaca 6, no. 1 (April 1, 2013): 35–41. http://dx.doi.org/10.2478/acs-2013-0007.
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Abstract The primary role of the biosensor is to specifically detect an analyte using biochemical reaction or interaction mediated by isolated biomolecules, organelles, whole cells or biomimetic receptors. In terms of construction and function, the biosensor consists of biorecognition element and transducer connected to suitable measurement device. Electrochemical biosensor is an electrode or microelectrode with the surface chemically modified by the biorecognition element. The main problem of analysis with the biosensors is the presence of low and high molecular weight substances in the sample that interfere at the detection of analyte. Due to deposition of surface active compounds the biosensor response may be diminished depending on time of interaction with sample. These effects can be eliminated by using anti-interference membranes. This review deals with preparation and utilization of membranes for the biocomponent immobilization and with outer-sphere protective membranes.
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Tian, Ding, Taoli Gu, Sai Nitin Yellamilli, and Chulsung Bae. "Phosphoric Acid-Doped Ion-Pair Coordinated PEMs with Broad Relative Humidity Tolerance." Energies 13, no. 8 (April 14, 2020): 1924. http://dx.doi.org/10.3390/en13081924.
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Proton exchange membrane (PEM) capable of working over a broad operating condition window is critical for successful adoption of PEM-based electrochemical devices. In this work, phosphoric acid (PA)-doped biphenyl-backbone ion-pair coordinated PEMs were prepared by quaternization of BPBr-100, a precursor polymer, with three different tertiary amines including trimethylamine, 1-methylpiperidine, and 1,2-dimethylimidazole followed by membrane casting, ion exchange reaction to hydroxide ion, and doping with PA. The resulting PA-doped ion-pair PEMs were characterized in terms of PA doping level, proton conductivity, relative humidity (RH) tolerance, thermal stability, and mechanical properties. PA doping levels were between six and eight according to acid-base titration. The size and structure of the cation group of ion-pair polymers were found to affect the PA doping level and water uptake. Proton conductivity was studied as a function of RH over a wide range of 5% to 95% RH. Stable conductivity at 80 °C was observed up to 70% RH for 10 h. Mechanical property characterization indicates that the PA doping process resulted in more ductile membranes with significantly increased elongation at break due to the plasticization effect of PA. A combination of high proton conductivity at low RH conditions, and good humidity tolerance makes this new class of PEMs great potential candidates for use in electrochemical devices such as proton exchange membrane fuel cells and electrochemical hydrogen compressors.
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Ravandeh, Mehdi, Dana Thal, Heike Kahlert, Kristian Wende, and Michael Lalk. "Self-assembled mono- and bilayers on gold electrodes to assess antioxidants—a comparative study." Journal of Solid State Electrochemistry 24, no. 11-12 (July 2, 2020): 3003–11. http://dx.doi.org/10.1007/s10008-020-04737-5.
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Abstract Oxidative stress is considered as an imbalance of reactive species over antioxidants, leading to diseases and cell death. Various methods have been developed to determine the antioxidant potential of natural or synthetic compounds based on the ability to scavenge free radicals. However, most of them lack biological relevance. Here, a gold-based self-assembled monolayer (SAM) was compared with a gold-supported lipid bilayer as models for the mammalian cell membrane to evaluate the free radical scavenging activity of different antioxidants. The oxidative damage induced by reactive species was verified by cyclic and differential pulse voltammetry and measured by the increase of electrochemical peak current of a redox probe. Trolox, caffeic acid (CA), epigallocatechin gallate (EGCG), ascorbic acid (AA), and ferulic acid (FA) were used as model antioxidants. The change in the decrease of the electrochemical signal reflecting oxidative membrane damage confirms the expected protective role. Both model systems showed similar efficacies of each antioxidant, the achieved order of radical scavenging potential is as follows: Trolox > CA > EGCG > AA > FA. The results showed that the electrochemical assay with SAM-modified electrodes is a stable and powerful tool to estimate qualitatively the antioxidative activity of a compound with respect to cell membrane protection against biologically relevant reactive species.