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This work shows the preparation of thin films, with thickness from 70 nm to 1 µm, of polybenzimidazole (m‐PBI) on polyimide P84 ® supports. Ethanolic solutions of m‐PBI are used to coat flat and hollow fiber supports of asymmetric P84 ® with PBI in a process where the coating and drying is performed at room temperature. A diluted solution of NaOH in EtOH allows the dissolution of the m‐PBI powder, providing the perfect coating solution to build thin films of m‐PBI without damaging the polymeric support. It also means a green alternative, avoiding the use toxic solvents, such as dimethylacetamide. The resulting membranes have been tested for the separation of H 2 mixtures at high temperature at different setups to allow checking their reproducibility. With 100 nm thickness the membranes showed their best gas separation performance. For flat membranes at 180 °C and 3 bar feed pressure a H 2 permeance of 48.5 GPU was obtained, with respective H 2 /CO 2 and H 2 /N 2 selectivities of 33.3 of 55.8. Besides, the hollow fibers under a feed pressure of 6 bar and tested at the same temperature showed near 90 GPU of H 2 with a H 2 /CO 2 selectivity of 13.5 in the one‐fiber module and over 39 GPU of H 2 with a H 2 /CO 2 selectivity of 20.2 in the five‐fiber module. Finally, the stability of the membranes has been proved for 22 days at 180 °C.
Javier Sánchez‐Laínez; Miren Etxeberria‐Benavides; Oana David; Carlos Téllez; Joaquín Coronas. Green Preparation of Thin Films of Polybenzimidazole on Flat and Hollow Fiber Supports: Application to Hydrogen Separation. ChemSusChem 2020, 14, 952 -960.
AMA StyleJavier Sánchez‐Laínez, Miren Etxeberria‐Benavides, Oana David, Carlos Téllez, Joaquín Coronas. Green Preparation of Thin Films of Polybenzimidazole on Flat and Hollow Fiber Supports: Application to Hydrogen Separation. ChemSusChem. 2020; 14 (3):952-960.
Chicago/Turabian StyleJavier Sánchez‐Laínez; Miren Etxeberria‐Benavides; Oana David; Carlos Téllez; Joaquín Coronas. 2020. "Green Preparation of Thin Films of Polybenzimidazole on Flat and Hollow Fiber Supports: Application to Hydrogen Separation." ChemSusChem 14, no. 3: 952-960.
There is a huge interest in developing novel hollow fiber (HF) membranes able to modulate neural differentiation to produce in vitro blood–brain barrier (BBB) models for biomedical and pharmaceutical research, due to the low cell-inductive properties of the polymer HFs used in current BBB models. In this work, poly(ε-caprolactone) (PCL) and composite PCL/graphene (PCL/G) HF membranes were prepared by phase inversion and were characterized in terms of mechanical, electrical, morphological, chemical, and mass transport properties. The presence of graphene in PCL/G membranes enlarged the pore size and the water flux and presented significantly higher electrical conductivity than PCL HFs. A biocompatibility assay showed that PCL/G HFs significantly increased C6 cells adhesion and differentiation towards astrocytes, which may be attributed to their higher electrical conductivity in comparison to PCL HFs. On the other hand, PCL/G membranes produced a cytotoxic effect on the endothelial cell line HUVEC presumably related with a higher production of intracellular reactive oxygen species induced by the nanomaterial in this particular cell line. These results prove the potential of PCL HF membranes to grow endothelial cells and PCL/G HF membranes to differentiate astrocytes, the two characteristic cell types that could develop in vitro BBB models in future 3D co-culture systems.
Marián Mantecón-Oria; Nazely Diban; Maria T. Berciano; Maria J. Rivero; Oana David; Miguel Lafarga; Olga Tapia; Ane Urtiaga. Hollow Fiber Membranes of PCL and PCL/Graphene as Scaffolds with Potential to Develop in vitro Blood–Brain Barrier Models. Membranes 2020, 10, 161 .
AMA StyleMarián Mantecón-Oria, Nazely Diban, Maria T. Berciano, Maria J. Rivero, Oana David, Miguel Lafarga, Olga Tapia, Ane Urtiaga. Hollow Fiber Membranes of PCL and PCL/Graphene as Scaffolds with Potential to Develop in vitro Blood–Brain Barrier Models. Membranes. 2020; 10 (8):161.
Chicago/Turabian StyleMarián Mantecón-Oria; Nazely Diban; Maria T. Berciano; Maria J. Rivero; Oana David; Miguel Lafarga; Olga Tapia; Ane Urtiaga. 2020. "Hollow Fiber Membranes of PCL and PCL/Graphene as Scaffolds with Potential to Develop in vitro Blood–Brain Barrier Models." Membranes 10, no. 8: 161.
There is a huge interest in developing novel hollow fiber (HF) membranes able to modulate neural differentiation to produce in vitro blood-brain barrier (BBB) models for biomedical and pharmaceutical research, due to the low cell-inductive properties of the polymer HFs used in current BBB models. In this work, poly(ε-caprolactone) (PCL) and composite PCL/graphene (PCL/G) HF membranes were prepared by phase inversion and were characterized in terms of mechanical, electrical, morphological, chemical, and mass transport properties. The presence of graphene in PCL/G membranes enlarged the pore size and the water flux and presented significantly higher electrical conductivity than PCL HFs. Biocompatibility assay showed that PCL/G HFs significantly increased C6 cells adhesion and differentiation towards astrocytes, may be attributed to their higher electrical conductivity in comparison to PCL HFs. On the other hand, PCL/G membranes produced a cytotoxic effect on the endothelial cell line HUVEC presumably related with a higher production of intracellular reactive oxygen species induced by the nanomaterial in this particular cell line. These results prove the potential of PCL HF membranes to grow endothelial cells and PCL/G HF membranes to differentiate astrocytes, the two characteristic cell types that could develop in vitro BBB models in future 3D co-culture systems.
Marián Mantecón-Oria; Nazely Diban; Maria T. Berciano; Maria J. Rivero; Oana David; Miguel Lafarga; Olga Tapia; Ane Urtiaga. Novel Hollow Fiber Membranes of PCL and PCL/Graphene as Scaffolds with Potential to Develop in vitro Blood-brain Barrier Models. 2020, 1 .
AMA StyleMarián Mantecón-Oria, Nazely Diban, Maria T. Berciano, Maria J. Rivero, Oana David, Miguel Lafarga, Olga Tapia, Ane Urtiaga. Novel Hollow Fiber Membranes of PCL and PCL/Graphene as Scaffolds with Potential to Develop in vitro Blood-brain Barrier Models. . 2020; ():1.
Chicago/Turabian StyleMarián Mantecón-Oria; Nazely Diban; Maria T. Berciano; Maria J. Rivero; Oana David; Miguel Lafarga; Olga Tapia; Ane Urtiaga. 2020. "Novel Hollow Fiber Membranes of PCL and PCL/Graphene as Scaffolds with Potential to Develop in vitro Blood-brain Barrier Models." , no. : 1.
The elimination of the additional defect healing post-treatment step in asymmetric hollow fiber manufacturing would result in a significant reduction in membrane production cost. However, obtaining integrally skinned polymeric asymmetric hollow fiber membranes with an ultrathin and defect-free selective layer is quite challenging. In this study, P84® asymmetric hollow fiber membranes with a highly thin (~56 nm) defect-free skin were successfully fabricated by fine tuning the dope composition and spinning parameters using volatile additive (tetrahydrofuran, THF) as key parameters. An extensive experimental and theoretical study of the influence of volatile THF addition on the solubility parameter of the N-methylpyrrolidone/THF solvent mixture was performed. Although THF itself is not a solvent for P84®, in a mixture with a good solvent for the polymer, like N-Methyl-2-pyrrolidone (NMP), it can be dissolved at high THF concentrations (NMP/THF ratio > 0.52). The as-spun fibers had a reproducible ideal CO2/N2 selectivity of 40, and a CO2 permeance of 23 GPU at 35 °C. The fiber production can be scaled-up with retention of the selectivity.
Miren Etxeberria-Benavides; Oguz Karvan; Freek Kapteijn; Jorge Gascon; Oana David. Fabrication of Defect-Free P84® Polyimide Hollow Fiber for Gas Separation: Pathway to Formation of Optimized Structure. Membranes 2019, 10, 4 .
AMA StyleMiren Etxeberria-Benavides, Oguz Karvan, Freek Kapteijn, Jorge Gascon, Oana David. Fabrication of Defect-Free P84® Polyimide Hollow Fiber for Gas Separation: Pathway to Formation of Optimized Structure. Membranes. 2019; 10 (1):4.
Chicago/Turabian StyleMiren Etxeberria-Benavides; Oguz Karvan; Freek Kapteijn; Jorge Gascon; Oana David. 2019. "Fabrication of Defect-Free P84® Polyimide Hollow Fiber for Gas Separation: Pathway to Formation of Optimized Structure." Membranes 10, no. 1: 4.
High performance and commercially attractive mixed-matrix membranes were developed for H2/CO2 separation via a scalable hollow fiber spinning process. Thin (~300 nm) and defect-free selective layers were successfully created with a uniform distribution of the nanosized (~60 nm) zeolitic-imidazole framework (ZIF-8) filler within the polymer (polybenzimidazole, PBI) matrix. These membranes were able to operate at high temperature (150 °C) and pressure (up to 30 bar) process conditions required in treatment of pre-combustion and syngas process gas streams. Compared with neat PBI hollow fibers, filler incorporation into the polymer matrix leads to a strong increase in H2 permeance from 65 GPU to 107 GPU at 150 °C and 7 bar, while the ideal H2/CO2 selectivity remained constant at 18. For mixed gas permeation, there is competition between H2 and CO2 transport inside ZIF-8 structure. Adsorption of CO2 in the nanocavities of the filler suppresses the transport of the faster permeating H2 and consequently decreases the H2 permeance with total feed pressure down to values equal to the pure PBI hollow fibers for the end pressure of 30 bar. Therefore, the improvement of fiber performance for gas separation with filler addition is compromised at high operating feed pressures, which emphasizes the importance of membrane evaluation under relevant process conditions.
Miren Etxeberria-Benavides; Timothy Johnson; Shuai Cao; Beatriz Zornoza; Joaquín Coronas; Javier Sanchez-Lainez; Anahid Sabetghadam; Xinlei Liu; Eduardo Andres-Garcia; Freek Kapteijn; Jorge Gascon; Oana David. PBI mixed matrix hollow fiber membrane: Influence of ZIF-8 filler over H2/CO2 separation performance at high temperature and pressure. Separation and Purification Technology 2019, 237, 116347 .
AMA StyleMiren Etxeberria-Benavides, Timothy Johnson, Shuai Cao, Beatriz Zornoza, Joaquín Coronas, Javier Sanchez-Lainez, Anahid Sabetghadam, Xinlei Liu, Eduardo Andres-Garcia, Freek Kapteijn, Jorge Gascon, Oana David. PBI mixed matrix hollow fiber membrane: Influence of ZIF-8 filler over H2/CO2 separation performance at high temperature and pressure. Separation and Purification Technology. 2019; 237 ():116347.
Chicago/Turabian StyleMiren Etxeberria-Benavides; Timothy Johnson; Shuai Cao; Beatriz Zornoza; Joaquín Coronas; Javier Sanchez-Lainez; Anahid Sabetghadam; Xinlei Liu; Eduardo Andres-Garcia; Freek Kapteijn; Jorge Gascon; Oana David. 2019. "PBI mixed matrix hollow fiber membrane: Influence of ZIF-8 filler over H2/CO2 separation performance at high temperature and pressure." Separation and Purification Technology 237, no. : 116347.
Electrocatalytic membrane reactors are becoming a viable solution for the treatment of wastewater contaminated with persistent organic pollutants and compounds.
Francois-Marie Allioux; Oana David; Andrea Merenda; James W. Maina; Miren Etxeberría-Benavides; David A. Pacheco Tanaka; Ludovic F. Dumée; Alfredo Pacheco Tanaka. Catalytic nickel and nickel–copper alloy hollow-fiber membranes for the remediation of organic pollutants by electrocatalysis. Journal of Materials Chemistry A 2018, 6, 6904 -6915.
AMA StyleFrancois-Marie Allioux, Oana David, Andrea Merenda, James W. Maina, Miren Etxeberría-Benavides, David A. Pacheco Tanaka, Ludovic F. Dumée, Alfredo Pacheco Tanaka. Catalytic nickel and nickel–copper alloy hollow-fiber membranes for the remediation of organic pollutants by electrocatalysis. Journal of Materials Chemistry A. 2018; 6 (16):6904-6915.
Chicago/Turabian StyleFrancois-Marie Allioux; Oana David; Andrea Merenda; James W. Maina; Miren Etxeberría-Benavides; David A. Pacheco Tanaka; Ludovic F. Dumée; Alfredo Pacheco Tanaka. 2018. "Catalytic nickel and nickel–copper alloy hollow-fiber membranes for the remediation of organic pollutants by electrocatalysis." Journal of Materials Chemistry A 6, no. 16: 6904-6915.
Carbon capture and storage (CCS) using membranes for the separation of CO2 holds great promise for the reduction of atmospheric CO2 emissions from fuel combustion and industrial processes. Among the different process outlines, post-combustion CO2 capture could be easily implemented in existing power plants. However, for this technology to become viable, new membrane materials have to be developed. In this article we present the development of high performance mixed matrix membranes (MMMs) composed of ZIF-94 filler and 6FDA-DAM polymer matrix. The CO2/N2 separation performance was evaluated by mixed gas tests (15CO2:85N2) at 25 °C and 1–4 bar transmembrane pressure difference. The CO2 membrane permeability was increased by the addition of the ZIF-94 particles, maintaining a constant CO2/N2 selectivity of ~22. The largest increase in CO2 permeability of ~ 200% was observed for 40 wt% ZIF-94 loading, reaching the highest permeability (2310 Barrer) at similar selectivity among 6FDA-DAM MMMs reported in literature. For the first time, the ZIF-94 metal organic framework crystals with particle size smaller than 500 nm were synthesized using nonhazardous solvent (tetrahydrofuran and methanol) instead of dimethylformamide (DMF) in a scalable process. Membranes were characterized by three non-invasive image techniques, i.e. SEM, AFM and nanoscale infrared imaging by scattering-type scanning near-field optical microscopy (s-SNOM). The combination of these techniques demonstrates a very good dispersion and interaction of the filler in the polymer layer, even at very high loadings.
Miren Etxeberria-Benavides; Oana David; Timothy Johnson; Magdalena M. Łozińska; Angelica Orsi; Paul A. Wright; Stefan Mastel; Rainer Hillenbrand; Freek Kapteijn; Jorge Gascon. High performance mixed matrix membranes (MMMs) composed of ZIF-94 filler and 6FDA-DAM polymer. Journal of Membrane Science 2017, 550, 198 -207.
AMA StyleMiren Etxeberria-Benavides, Oana David, Timothy Johnson, Magdalena M. Łozińska, Angelica Orsi, Paul A. Wright, Stefan Mastel, Rainer Hillenbrand, Freek Kapteijn, Jorge Gascon. High performance mixed matrix membranes (MMMs) composed of ZIF-94 filler and 6FDA-DAM polymer. Journal of Membrane Science. 2017; 550 ():198-207.
Chicago/Turabian StyleMiren Etxeberria-Benavides; Oana David; Timothy Johnson; Magdalena M. Łozińska; Angelica Orsi; Paul A. Wright; Stefan Mastel; Rainer Hillenbrand; Freek Kapteijn; Jorge Gascon. 2017. "High performance mixed matrix membranes (MMMs) composed of ZIF-94 filler and 6FDA-DAM polymer." Journal of Membrane Science 550, no. : 198-207.
The sintering of metal powders is an efficient and versatile technique to fabricate porous metal elements such as filters, diffusers, and membranes. Neck formation between particles is, however, critical to tune the porosity and optimize mass transfer in order to minimize the densification process. In this work, macro-porous stainless steel (SS) hollow-fibers (HFs) were fabricated by the extrusion and sintering of a dope comprised, for the first time, of a bimodal mixture of SS powders. The SS particles of different sizes and shapes were mixed to increase the neck formation between the particles and control the densification process of the structure during sintering. The sintered HFs from particles of two different sizes were shown to be more mechanically stable at lower sintering temperature due to the increased neck area of the small particles sintered to the large ones. In addition, the sintered HFs made from particles of 10 and 44 μm showed a smaller average pore size (<1 μm) as compared to the micron-size pores of sintered HFs made from particles of 10 μm only and those of 10 and 20 μm. The novel HFs could be used in a range of applications, from filtration modules to electrochemical membrane reactors.
Francois-Marie Allioux; Oana Cristina David; Miren Etxeberria Benavides; Lingxue Kong; David Alfredo Pacheco Tanaka; Ludovic F. Dumée. Preparation of Porous Stainless Steel Hollow-Fibers through Multi-Modal Particle Size Sintering towards Pore Engineering. Membranes 2017, 7, 40 .
AMA StyleFrancois-Marie Allioux, Oana Cristina David, Miren Etxeberria Benavides, Lingxue Kong, David Alfredo Pacheco Tanaka, Ludovic F. Dumée. Preparation of Porous Stainless Steel Hollow-Fibers through Multi-Modal Particle Size Sintering towards Pore Engineering. Membranes. 2017; 7 (3):40.
Chicago/Turabian StyleFrancois-Marie Allioux; Oana Cristina David; Miren Etxeberria Benavides; Lingxue Kong; David Alfredo Pacheco Tanaka; Ludovic F. Dumée. 2017. "Preparation of Porous Stainless Steel Hollow-Fibers through Multi-Modal Particle Size Sintering towards Pore Engineering." Membranes 7, no. 3: 40.
Positive thermal expansion coefficients (TEC) of 52·10-6 and 35·10-6 K-1 were experimentally calculated in the -116 - 250 ºC range for the III-phases of zeolitic imidazolate frameworks (ZIF) ZIF-9(Co) and ZIF-7(Zn), respectively, by means of the unit cell dimensions and volume of the materials in the monoclinic crystal system calculated from the XRD patterns. The unit cell dimensions and volume showed a significant expansion phenomenon as the temperature increased, by as much as 5.5 % for ZIF-9-III in the studied range. To exploit the advantages of such thermal behavior, a new approach to the fabrication of ZIF-9-III membranes on thin, flexible and highly porous nickel hollow fiber (Ni HF) supports by a versatile and easy-controllable microfluidic setup is herein reported. These Ni HF supports result from the sintering of 25-µm Ni particles and display very positive mechanical properties and bending resistance. As compared to the traditional polymer-based HF membranes, the ZIF metal-supported membrane exhibited good durability and robustness throughout its operation in a wide temperature range and after heating and cooling cycles. These benefits derive from (1) the pore-plugging membrane configuration resulting from the high porosity of the support, and (2) the similarity between the TECs of the ZIF and the metallic support, both positive, which enhances their mutual compatibility. An increase in the H2/CO2 separation selectivity at low temperatures (as high as 22.2 at -10 ºC, along with 102 GPU permeance of H2) was achieved, in agreement with the structural variations observed in the ZIF material.
Fernando Cacho-Bailo; Miren Etxeberria-Benavides; Oana David; Carlos Téllez; Joaquin Coronas. Structural Contraction of Zeolitic Imidazolate Frameworks: Membrane Application on Porous Metallic Hollow Fibers for Gas Separation. ACS Applied Materials & Interfaces 2017, 9, 20787 -20796.
AMA StyleFernando Cacho-Bailo, Miren Etxeberria-Benavides, Oana David, Carlos Téllez, Joaquin Coronas. Structural Contraction of Zeolitic Imidazolate Frameworks: Membrane Application on Porous Metallic Hollow Fibers for Gas Separation. ACS Applied Materials & Interfaces. 2017; 9 (24):20787-20796.
Chicago/Turabian StyleFernando Cacho-Bailo; Miren Etxeberria-Benavides; Oana David; Carlos Téllez; Joaquin Coronas. 2017. "Structural Contraction of Zeolitic Imidazolate Frameworks: Membrane Application on Porous Metallic Hollow Fibers for Gas Separation." ACS Applied Materials & Interfaces 9, no. 24: 20787-20796.
Porous poly(benzimidazole) (PBI) membranes of low vanadium ions permeability are described for an all vanadium redox flow battery (VRFB). The PBI membrane was prepared by a water vapour induced phase inversion process of a PBI polymer solution. The membrane has a symmetrical cross-sectional morphology. A low water permeability of 16.5 L (m2 h bar)−1 indicates the high hydraulic resistance stemming from a closed cell morphology with nanoporous characteristics. The PBI membrane doped with 2.5 M H2SO4 shows a proton conductivity of 16.6 mS cm−1 and VO2+ permeability as low as 4.5 × 10−8 cm2 min−1. The stability test of dense PBI membrane in VO2+ solution indicates good chemical stability. An all vanadium redox flow battery (VRFB) operated with the porous PBI membrane shows 98% coulombic efficiency and more than 10% higher energy efficiency compared to VRFB operated with Nafion 112 at applied current densities of 20–40 mA cm−2. High in situ stability of the porous PBI membrane was confirmed by about 50 cycles of continuous charge and discharge operation of the battery.
Tao Luo; Oana David; Youri Gendel; Matthias Wessling. Porous poly(benzimidazole) membrane for all vanadium redox flow battery. Journal of Power Sources 2016, 312, 45 -54.
AMA StyleTao Luo, Oana David, Youri Gendel, Matthias Wessling. Porous poly(benzimidazole) membrane for all vanadium redox flow battery. Journal of Power Sources. 2016; 312 ():45-54.
Chicago/Turabian StyleTao Luo; Oana David; Youri Gendel; Matthias Wessling. 2016. "Porous poly(benzimidazole) membrane for all vanadium redox flow battery." Journal of Power Sources 312, no. : 45-54.
We report a novel tubular electrochemical cell which is operated in a cyclic adsorption – electro-Fenton process and by this means overcomes the drawbacks of the traditional electro-Fenton process. A microtube made only of multi-walled carbon nanotubes (MWCNT) functions as a gas diffusion electrode (GDE) and highly porous adsorber. In the process, the pollutants were first removed electroless from the wastewater by adsorption on the MWCNT-GDE. Subsequently, the pollutants are electrochemically degraded in a defined volume of electrolyte solution using the electro-Fenton process. Oxygen was supplied into the lumen of the saturated microtubular GDE which was surrounded by a cylindrical anode made of Ti-felt coated with Pt/IrO2 catalysts. For the proof of concept the model pollutant Acid Red 14 (AR14), an azo dye, was used. The decomposition of AR14 was studied at different applied current densities and initial concentrations of ferrous iron in the electrolyte solution. At optimal conditions, complete regeneration of the adsorption capacity of the MWCNT-GDE, complete decolorization and TOC and COD removal rates of 50% and 70% were achieved, respectively. The MWCNT-GDE is regenerated and again available for adsorption. This approach allows water treatment independent of its composition, thus does not require any addition of chemicals to the wastewater.
Hannah Roth; Youri Gendel; Pompilia Buzatu; Oana David; Matthias Wessling. Tubular carbon nanotube-based gas diffusion electrode removes persistent organic pollutants by a cyclic adsorption – Electro-Fenton process. Journal of Hazardous Materials 2016, 307, 1 -6.
AMA StyleHannah Roth, Youri Gendel, Pompilia Buzatu, Oana David, Matthias Wessling. Tubular carbon nanotube-based gas diffusion electrode removes persistent organic pollutants by a cyclic adsorption – Electro-Fenton process. Journal of Hazardous Materials. 2016; 307 ():1-6.
Chicago/Turabian StyleHannah Roth; Youri Gendel; Pompilia Buzatu; Oana David; Matthias Wessling. 2016. "Tubular carbon nanotube-based gas diffusion electrode removes persistent organic pollutants by a cyclic adsorption – Electro-Fenton process." Journal of Hazardous Materials 307, no. : 1-6.
Thin and mechanically stable proton-exchange membranes with high V(IV) barrier properties and good proton conductivity have been fabricated by polymer blending of sulfonated poly(ether ether ketone) with polyaniline. V(IV) diffusion coefficient of blended membranes in a wt. ratio of 80/20 was 2.6 and 6 times lower than for pure sulfonated poly(ether ether ketone) and Nafion 112 membrane, respectively. This behaviour is assumed to be caused by a densified polymer matrix given by acid/base interactions between the two polymers. Blended membranes in a wt. ratio of 80/20 had a good proton conductivity of 54.15 mS cm−1 and ion exchange capacity of 1.44 mmol g−1. The membranes were also characterized in all-vanadium redox flow battery, where only slightly higher efficiencies were achieved than for pure polymer. Slow PANI degradation determines a decrease in membrane performance, reaching values close to the starting polymer (SPEEK-E600). Therefore, the application of blended membranes in the all-vanadium redox flow battery is not advantageous. However, the improved barrier properties are likely to be beneficial for their application in vanadium/air-redox flow battery in order to reduce oxygen crossover. In the latter, no V(V) ions can oxidize the blend polymer.
Oana David; Korcan Percin; Tao Luo; Youri Gendel; Matthias Wessling. Proton-exchange membranes based on sulfonated poly(ether ether ketone)/polyaniline blends for all- and air-vanadium redox flow battery applications. Journal of Energy Storage 2015, 1, 65 -71.
AMA StyleOana David, Korcan Percin, Tao Luo, Youri Gendel, Matthias Wessling. Proton-exchange membranes based on sulfonated poly(ether ether ketone)/polyaniline blends for all- and air-vanadium redox flow battery applications. Journal of Energy Storage. 2015; 1 ():65-71.
Chicago/Turabian StyleOana David; Korcan Percin; Tao Luo; Youri Gendel; Matthias Wessling. 2015. "Proton-exchange membranes based on sulfonated poly(ether ether ketone)/polyaniline blends for all- and air-vanadium redox flow battery applications." Journal of Energy Storage 1, no. : 65-71.
We report a microtubular gas diffusion electrodes made of multi-walled carbon nanotubes (MWCNT). The electrodes were prepared by inside-out cake filtration of an aqueous MWCNT suspension onto a microfiltration hollow fiber (HF) membrane, followed by washing out the surfactant, drying and removal of the all CNT microtube from the HF membrane. Length, outer diameter, and wall thickness of the tubular electrodes are: up to 44 cm, ~ 1.7 mm and 275 μm, respectively. The BET surface area is 200 m2/g with a porosity of 48–67% and an electrical conductivity of ~ 20 S/cm. Application of this microtubular Gas Diffusion Electrodes (GDE) was studied for the oxygen reduction reaction (ORR) in divided and undivided electrochemical cells. Oxygen supply into the lumen of the tubular electrodes resulted in much higher current densities for ORR than in experiments where the electrolyte was saturated by bubbling with pure oxygen. Within the 0.25–1.0 bar pressure (gauge) region, higher ORR rates were achieved at lower pressure. We also show that H2O2 production is possible using the new GDE. We propose to use such novel electrodes for the fabrication of tubular electrochemical reactors, e.g. fuel cells, H2O2 generators, CO2 reduction and other processes that involve GDE application.
Youri Gendel; Hannah Roth; Alexandra Rommerskirchen; Oana David; Matthias Wessling. A microtubular all CNT gas diffusion electrode. Electrochemistry Communications 2014, 46, 44 -47.
AMA StyleYouri Gendel, Hannah Roth, Alexandra Rommerskirchen, Oana David, Matthias Wessling. A microtubular all CNT gas diffusion electrode. Electrochemistry Communications. 2014; 46 ():44-47.
Chicago/Turabian StyleYouri Gendel; Hannah Roth; Alexandra Rommerskirchen; Oana David; Matthias Wessling. 2014. "A microtubular all CNT gas diffusion electrode." Electrochemistry Communications 46, no. : 44-47.
We report batch and continuous electrochemical desalination utilizing the ion adsorption capacity of a slurry containing carbon particles. Two carbon suspensions and the feed water are fed into the electrochemical cell operated according to the principle of membrane assisted capacitive deionization (MCDI). In a batch mode operation after the desalination step is complete the adsorbed ions are discharged from flowing electrodes to the same portion of water using polarity reversal. Operation with 15 g NaCl/l water solution resulted in extremely high apparent salt adsorption capacity (SAC) value of 260 mg/gdry carbon. This value is much higher than the highest value of SAC reported until now — 14.3 mg/g. The reason for this phenomenon is not clear and further research is currently performed. In a new truly continuous process, both slurry streams are continuously recirculated between the desalination module and a regeneration/concentration module operated with the same functionality but with reversed potential. Ions desorb from the flowing electrodes and concentrate through the membranes into a purge stream. We prove continuous operation with desalination rate of more than 99% for an initial salt concentration of 1 g NaCl/l. Concentration factors depend on the recovery, with 90% water recovery being demonstrated easily.
Youri Gendel; Alexandra Klara Elisabeth Rommerskirchen; Oana David; Matthias Wessling. Batch mode and continuous desalination of water using flowing carbon deionization (FCDI) technology. Electrochemistry Communications 2014, 46, 152 -156.
AMA StyleYouri Gendel, Alexandra Klara Elisabeth Rommerskirchen, Oana David, Matthias Wessling. Batch mode and continuous desalination of water using flowing carbon deionization (FCDI) technology. Electrochemistry Communications. 2014; 46 ():152-156.
Chicago/Turabian StyleYouri Gendel; Alexandra Klara Elisabeth Rommerskirchen; Oana David; Matthias Wessling. 2014. "Batch mode and continuous desalination of water using flowing carbon deionization (FCDI) technology." Electrochemistry Communications 46, no. : 152-156.
We present tubular macroporous titanium membranes prepared via a dry-wet spinning process from a polyethersulfone solution loaded with Ti particles (15 μm) and a subsequent sintering process at various sintering temperatures (1100–1500 °C) and sintering times (30–75 min). Outer diameter, wall thickness, average pore size and porosity of the Ti tubes were ~4.5 mm, ~350 μm, 1.6–2.8 μm and ~30%, respectively. These tubular membranes have excellent mechanical strength, electrical conductivity as well as nitrogen and water permeability. These properties, together with the inherent high corrosion and temperature resistance of titanium make them suitable for a wide range of membrane applications such as microfiltration, porous tubular electrodes for electrochemical membrane reactors; and gas-to-liquid diffuser.
Oana David; Youri Gendel; Matthias Wessling. Tubular macro-porous titanium membranes. Journal of Membrane Science 2014, 461, 139 -145.
AMA StyleOana David, Youri Gendel, Matthias Wessling. Tubular macro-porous titanium membranes. Journal of Membrane Science. 2014; 461 ():139-145.
Chicago/Turabian StyleOana David; Youri Gendel; Matthias Wessling. 2014. "Tubular macro-porous titanium membranes." Journal of Membrane Science 461, no. : 139-145.
Microtubes made of multi-walled carbon nanotubes were prepared via infiltration of CNT-suspension through a microfiltration hollow fiber membrane. Shrinking of the entangled CNT network during the drying allows withdrawal of CNT-microtubes from the hollow fiber. Currently, microtubes have a length of ∼50 cm, outer diameter of ∼1.7 mm and scalable inner diameter by varying the infiltration time resulting in wall thicknesses of 130–320 μm. The BET surface area is 200 m2/g with a porosity of 48–67% and an electrical conductivity ∼20 S/cm. We propose to use such novel CNT-microtubes for the fabrication of tubular electrochemical cells and membrane filtration processes.
Youri Gendel; Oana Cristina David; Matthias Wessling. Microtubes made of carbon nanotubes. Carbon 2013, 68, 818 -820.
AMA StyleYouri Gendel, Oana Cristina David, Matthias Wessling. Microtubes made of carbon nanotubes. Carbon. 2013; 68 ():818-820.
Chicago/Turabian StyleYouri Gendel; Oana Cristina David; Matthias Wessling. 2013. "Microtubes made of carbon nanotubes." Carbon 68, no. : 818-820.
The application of hollow fiber membranes for the separation of industrial gas mixtures relies on the correct characterization of the permeation of the involved gaseous components through the hollow fiber membranes. Thus, this study is focused on the characterization of the permeation through Matrimid® hollow fiber membranes of four gas mixtures containing H2 (H2/N2, H2/CO, H2/CO2), and the quaternary gas mixture H2/N2/CO/CO2, working at a constant temperature of 303 K and pressures up to 10 bar. The main differences and similarities in the gas permeation properties of hollow fibers with respect to flat membranes, as well as in the permeation of gas mixtures with respect to pure gases, are discussed. Our results suggest that for mixtures containing H2 and CO2 hollow fiber membranes perform better than flat membranes given that a lower depression in the permeability of H2 has been observed. At 2.3 bar feed pressure, ideal selectivity values obtained for H2/N2, H2/CO and H2/CO2 gas pairs were 74.4, 42.6 and 5 respectively, with a H2 permeance of 50.2×10−8 m3(STP) m−2 s−1 kPa−1. The specific behavior observed in the permeation through hollow fiber has been explained by a combination of different phenomena such as hollow fiber membrane substructure resistance, CO2 induced plasticization and competitive sorption effects between the components of the gaseous mixtures
Oana Cristina David; Daniel Gorri; Kitty Nijmeijer; Inmaculada Ortiz; Ane Urtiaga. Hydrogen separation from multicomponent gas mixtures containing CO, N2 and CO2 using Matrimid® asymmetric hollow fiber membranes. Journal of Membrane Science 2012, 419-420, 49 -56.
AMA StyleOana Cristina David, Daniel Gorri, Kitty Nijmeijer, Inmaculada Ortiz, Ane Urtiaga. Hydrogen separation from multicomponent gas mixtures containing CO, N2 and CO2 using Matrimid® asymmetric hollow fiber membranes. Journal of Membrane Science. 2012; 419-420 ():49-56.
Chicago/Turabian StyleOana Cristina David; Daniel Gorri; Kitty Nijmeijer; Inmaculada Ortiz; Ane Urtiaga. 2012. "Hydrogen separation from multicomponent gas mixtures containing CO, N2 and CO2 using Matrimid® asymmetric hollow fiber membranes." Journal of Membrane Science 419-420, no. : 49-56.
This study is focused on the design of a liquid phase system to be used in facilitated transport-supported ionic liquid membranes (SILMs) for the recovery of carbon monoxide from gaseous streams based on the ability of CO molecules to form π complexation bounds with Cu+ ion. As liquid phase we propose the use of the ionic liquid 1-hexyl-3-methyl-imidazolium chlorocuprate prepared by the direct mixture of copper(I) chloride (CuCl) with 1-hexyl-3-methylimidazolium chloride ([hmim][Cl]). A comprehensive look at the reaction mechanism and the equilibrium parameters obtained from the experimental characterization of the physical and chemical solubility of carbon monoxide in pure [hmim][Cl], and in mixtures CuCl/[hmim][Cl] is presented. The gas equilibrium solubility experimental work was carried out in the CuCl/[hmim][Cl] molar ratio range from 0 to 0.75, temperature from 273.15 to 303.15 K and pressures up to 20 bar. The values of the Henry’s law constant for the physical solubility of CO in [hmim][Cl] changed from 15.3 × 10−3 to 2.7 × 10−3 mol kg−1 bar−1 as the temperature increased from 273.15 to 293.15 K. The chemical solubility of CO in the reactive ionic liquid media increased with the increase of the concentration of CuCl, with the increase of pressure and as temperature decreases. In the operation range of variables the maximum absorption of CO was of 2.26 mol kg−1 that was reached working at 20 bar, at CuCl/[hmim][Cl] molar ratio of 0.75 and 273.15 K.
Oana Cristina David; Gabriel Zarca; Daniel Gorri; Ane Urtiaga; Inmaculada Ortiz. On the improved absorption of carbon monoxide in the ionic liquid 1-hexyl-3-methylimidazolium chlorocuprate. Separation and Purification Technology 2012, 97, 65 -72.
AMA StyleOana Cristina David, Gabriel Zarca, Daniel Gorri, Ane Urtiaga, Inmaculada Ortiz. On the improved absorption of carbon monoxide in the ionic liquid 1-hexyl-3-methylimidazolium chlorocuprate. Separation and Purification Technology. 2012; 97 ():65-72.
Chicago/Turabian StyleOana Cristina David; Gabriel Zarca; Daniel Gorri; Ane Urtiaga; Inmaculada Ortiz. 2012. "On the improved absorption of carbon monoxide in the ionic liquid 1-hexyl-3-methylimidazolium chlorocuprate." Separation and Purification Technology 97, no. : 65-72.
Oana Cristina David; Daniel Gorri; K. Nijmeijer; Inmaculada Ortiz; A. Urtiaga. Hydrogen Separation from Multicomponent Gas Mixtures Containing CO, N2 and CO2 Using Matrimid Asymmetric Hollow Fiber Membranes. Procedia Engineering 2012, 44, 1117 -1118.
AMA StyleOana Cristina David, Daniel Gorri, K. Nijmeijer, Inmaculada Ortiz, A. Urtiaga. Hydrogen Separation from Multicomponent Gas Mixtures Containing CO, N2 and CO2 Using Matrimid Asymmetric Hollow Fiber Membranes. Procedia Engineering. 2012; 44 ():1117-1118.
Chicago/Turabian StyleOana Cristina David; Daniel Gorri; K. Nijmeijer; Inmaculada Ortiz; A. Urtiaga. 2012. "Hydrogen Separation from Multicomponent Gas Mixtures Containing CO, N2 and CO2 Using Matrimid Asymmetric Hollow Fiber Membranes." Procedia Engineering 44, no. : 1117-1118.
In this work, the membrane separation of hydrogen from binary, ternary and quaternary mixtures of H2, N2, CO and CO2 is presented. Hydrogen permeability through a polyimide Matrimid 5218 membrane was experimentally obtained using the constant pressure technique. The influence of the feed gas composition, temperature (30–100 °C), pressure range (up to 6 bar), and flow rates was experimentally analyzed. As expected, the pure gas permeability of H2 was only slightly dependant on pressure and had an average value of 17.7 × 10−14 m3(STP) m m−2 s−1 kPa−1 at 30 °C. Hydrogen permeability was not affected by the presence of nitrogen and carbon monoxide, and as a result the mixed gas selectivities for the H2/N2/CO mixtures are very close to the selectivities calculated from pure gas permeation data. On the contrary, a strong dependency of the hydrogen permeability on CO2 concentration was observed even at low concentrations of CO2. A reduction of 42% of the hydrogen permeability coefficient was obtained when a mixture of 10/90 vol.% H2/CO2 was used as feed gas. Accordingly H2/CO2 selectivity decayed from a value of 4.2 calculated from pure gas permeabilities to 2.7 when permeation data were obtained in mixed gas experiments. The preferential sorption of CO2 on the Langmuir sites of the excess free volume portion of the polymer allowed explaining and quantifying this phenomenon. The “dual-mode sorption, partial immobilization” model was used to describe H2 and CO2 permeation behavior of pure, binary, ternary and quaternary mixtures. The model sorption parameters for N2 and CO2 in the polymer Matrimid 5218 were obtained from the literature meanwhile those for H2 and for CO were unknown and resulted from the fitting of the experimental data to the proposed model. Satisfactory agreement between predicted permeability results and experimental data with a correlation coefficient (R) higher than 0.95 and mean squared relative error (MSRE) lower than 0.01 was attained. Thus, this work reports useful knowledge related to the intrinsic material properties, considering gas mixtures of industrial interest and essential when other membrane configurations like hollow fibers, mixed matrix membranes or polymer blends are proposed.
Oana Cristina David; Daniel Gorri; Ana Urtiaga; Inmaculada Ortiz. Mixed gas separation study for the hydrogen recovery from H2/CO/N2/CO2 post combustion mixtures using a Matrimid membrane. Journal of Membrane Science 2011, 378, 359 -368.
AMA StyleOana Cristina David, Daniel Gorri, Ana Urtiaga, Inmaculada Ortiz. Mixed gas separation study for the hydrogen recovery from H2/CO/N2/CO2 post combustion mixtures using a Matrimid membrane. Journal of Membrane Science. 2011; 378 (1-2):359-368.
Chicago/Turabian StyleOana Cristina David; Daniel Gorri; Ana Urtiaga; Inmaculada Ortiz. 2011. "Mixed gas separation study for the hydrogen recovery from H2/CO/N2/CO2 post combustion mixtures using a Matrimid membrane." Journal of Membrane Science 378, no. 1-2: 359-368.