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Yanase S, Kikawada Y, Oi T. Applicability of self-consistent reaction field (SCRF) method to DFT estimation of hydrogen isotope separation factors in reversible processes. Isotopes Environ Health Stud 2024:1-14. [PMID: 38597681 DOI: 10.1080/10256016.2024.2336470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 03/21/2024] [Indexed: 04/11/2024]
Abstract
In earlier quantum chemical calculations of isotope effects, chemical species in the liquid phase were generally treated as existing in the gas phase. In recent years, however, advances in computational programs have made it easier for the self-consistent reaction field (SCRF) method to handle chemical species in the liquid phase, and as a result, it has become easier to apply the SCRF method to isotope effect calculations. This paper concerns the scope of application of the DFT-SCRF method to reversible processes for hydrogen isotope enrichment. It is found that the applicability of the method depends on the type of the intermolecular interaction in the liquid phase and the degree of hydrogen isotope effect (separation factor) on which the process is based. When the magnitude of the isotope effect of the separation system is greater than 10-1, the simple SCRF method is fully applicable; when the magnitude is around 10-2, SCRF with a dimer model, in which the monomer is replaced by a dimer, is applicable for the analysis of the liquid phase with relatively strong intermolecular interactions. Anharmonic correction to the separation factor calculated based on harmonic frequencies may be effective to systems with the liquid phase with weak intermolecular interactions.
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Affiliation(s)
- Satoshi Yanase
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
| | - Yoshikazu Kikawada
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
| | - Takao Oi
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, Tokyo, Japan
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Bhoumick MC, Paul S, Roy S, Harvey BG, Mitra S. Recovery of Isoamyl Alcohol by Graphene Oxide Immobilized Membrane and Air-Sparged Membrane Distillation. Membranes (Basel) 2024; 14:49. [PMID: 38392676 PMCID: PMC10890467 DOI: 10.3390/membranes14020049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/31/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024]
Abstract
Isoamyl alcohol is an important biomass fermentation product that can be used as a gasoline surrogate, jet fuel precursor, and platform molecule for the synthesis of fine chemicals and pharmaceuticals. This study reports on the use of graphene oxide immobilized membra (GOIMs) for the recovery of isoamyl alcohol from an aqueous matrix. The separation was performed using air-sparged membrane distillation (ASMD). In contrast to a conventional PTFE membrane, which exhibited minimal separation, preferential adsorption on graphene oxide within GOIMs resulted in highly selective isoamyl alcohol separation. The separation factor reached 6.7, along with a flux as high as 1.12 kg/m2 h. Notably, the overall mass transfer coefficients indicated improvements with a GOIM. Optimization via response surfaces showed curvature effects for the separation factor due to the interaction effects. An empirical model was generated based on regression equations to predict the flux and separation factor. This study demonstrates the potential of GOIMs and ASMD for the efficient recovery of higher alcohols from aqueous solutions, highlighting the practical applications of these techniques for the production of biofuels and bioproducts.
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Affiliation(s)
- Mitun Chandra Bhoumick
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Sumona Paul
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Sagar Roy
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Benjamin G Harvey
- Naval Air Warfare Center, Weapons Division, Research Department, Chemistry Division, China Lake, CA 93555, USA
| | - Somenath Mitra
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ 07102, USA
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Yang M, Zhu JJ, McGaughey A, Zheng S, Priestley RD, Ren ZJ. Predicting Extraction Selectivity of Acetic Acid in Pervaporation by Machine Learning Models with Data Leakage Management. Environ Sci Technol 2023; 57:5934-5946. [PMID: 36972410 DOI: 10.1021/acs.est.2c06382] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The extraction of acetic acid and other carboxylic acids from water is an emerging separation need as they are increasingly produced from waste organics and CO2 during carbon valorization. However, the traditional experimental approach can be slow and expensive, and machine learning (ML) may provide new insights and guidance in membrane development for organic acid extraction. In this study, we collected extensive literature data and developed the first ML models for predicting separation factors between acetic acid and water in pervaporation with polymers' properties, membrane morphology, fabrication parameters, and operating conditions. Importantly, we assessed seed randomness and data leakage problems during model development, which have been overlooked in ML studies but will result in over-optimistic results and misinterpreted variable importance. With proper data leakage management, we established a robust model and achieved a root-mean-square error of 0.515 using the CatBoost regression model. In addition, the prediction model was interpreted to elucidate the variables' importance, where the mass ratio was the topmost significant variable in predicting separation factors. In addition, polymers' concentration and membranes' effective area contributed to information leakage. These results demonstrate ML models' advances in membrane design and fabrication and the importance of vigorous model validation.
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Affiliation(s)
- Meiqi Yang
- Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey08544, United States
| | - Jun-Jie Zhu
- Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey08544, United States
| | - Allyson McGaughey
- Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey08544, United States
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey08544, United States
| | - Sunxiang Zheng
- Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey08544, United States
| | - Rodney D Priestley
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey08544, United States
| | - Zhiyong Jason Ren
- Department of Civil and Environmental Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey08544, United States
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Bakdash RS, Aljundi IH, Basheer C, Abdulazeez I, Al‐Saadi AA. Porous Fluorocarbon from Rice Husk for the Efficient Separation of Gases. Glob Chall 2021; 5:2000124. [PMID: 34267928 PMCID: PMC8272015 DOI: 10.1002/gch2.202000124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/13/2021] [Indexed: 06/13/2023]
Abstract
A porous fluorocarbon sorbent is synthesized from rice husk (RH) in a microwave reactor and then evaluated for the adsorption of different gases (CH4, CO2, and N2). The fluorocarbon is characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Raman spectroscopy, Thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Significant enhancement in the surface area of activated carbon material is obtained from 29 to 531 m2 g-1 after removing naturally present silica in RH. Results reveal that rice husk fluorocarbon (RHF) has a higher adsorption affinity for CO2 (1.8 mmol g-1) than that of the sulfonated rice husk (RHS) (1.4 mmol g-1) at 298 K while the corresponding separation factor of CO2/CH4 is 4 and 3; respectively. Higher separation factors of 12 and 10 are observed for the binary system of CO2/N2, respectively. Quantum chemical density functional theory (DFT) calculations agree with the experimental observations. They reveal that RHF exhibits strong columbic interactions with considerable interaction energies of -87.85, -76.75, and -55.65 kcal mol-1 with CO2, CH4, and N2 gases; respectively. Finally, the adsorption process results are highly reproducible, with a small decrease in the adsorption capacity of less than 5% after repeated trials.
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Affiliation(s)
- Rashed S. Bakdash
- Department of ChemistryKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia
| | - Isam H. Aljundi
- Department of Chemical EngineeringKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia
| | - Chanbasha Basheer
- Department of ChemistryKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia
| | - Ismail Abdulazeez
- Department of ChemistryKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia
| | - Abdulaziz A. Al‐Saadi
- Department of ChemistryKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia
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Khan MI, Shanableh A, Elboughdiri N, Kriaa K, Ghernaout D, Ghareba S, Khraisheh M, Lashari MH. Higher Acid Recovery Efficiency of Novel Functionalized Inorganic/Organic Composite Anion Exchange Membranes from Acidic Wastewater. Membranes (Basel) 2021; 11:membranes11020133. [PMID: 33672853 PMCID: PMC7918162 DOI: 10.3390/membranes11020133] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/07/2021] [Accepted: 02/10/2021] [Indexed: 01/31/2023]
Abstract
In this work, the synthesis of a series of the functionalized inorganic/organic composite anion exchange membranes (AEMs) was carried out by employing the varying amount of inorganic filler consist of N-(trimethoxysilylpropyl)-N,N,N-trimethylammonium chloride (TMSP-TMA+Cl-) into the quaternized poly (2, 6-dimethyl-1, 4-phenylene oxide) (QPPO) matrix for acid recovery via diffusion dialysis (DD) process. Fourier transform infrared (FTIR) spectroscopy clearly demonstrated the fabrication of the functionalized inorganic/organic composite AEMs and the subsequent membrane characteristic measurements such as ion exchange capacity (IEC), linear swelling ratio (LSR), and water uptake (WR) gave us the optimum loading condition of the filler without undesirable filler particle aggregation. These composite AEMs exhibited IEC of 2.18 to 2.29 meq/g, LSR of 13.33 to 18.52%, and WR of 46.11 to 81.66% with sufficient thermal, chemical, and mechanical stability. The diffusion dialysis (DD) test for acid recovery from artificial acid wastewater of HCl/FeCl2 showed high acid DD coefficient (UH+) (0.022 to 0.025 m/h) and high separation factor (S) (139-260) compared with the commercial membrane. Furthermore, the developed AEMs was acceptably stable (weight loss < 20%) in the acid wastewater at 60 °C as an accelerated severe condition for 2 weeks. These results clearly indicated that the developed AEMs have sufficient potential for acid recovery application by DD process.
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Affiliation(s)
- Muhammad Imran Khan
- Research Institute of Sciences and Engineering, University of Sharjah, Sharjah 27272, United Arab Emirates;
- Correspondence: ; Tel.: +971-563-404-827
| | - Abdallah Shanableh
- Research Institute of Sciences and Engineering, University of Sharjah, Sharjah 27272, United Arab Emirates;
| | - Noureddine Elboughdiri
- Chemical Engineering Department, College of Engineering, University of Ha’il, P.O. Box 2440, Ha’il 81441, Saudi Arabia; (N.E.); (D.G.); (S.G.)
- Chemical Engineering Process Department, National School of Engineering Gabes, University of Gabes, Gabes 6011, Tunisia;
| | - Karim Kriaa
- Chemical Engineering Process Department, National School of Engineering Gabes, University of Gabes, Gabes 6011, Tunisia;
- Chemical Engineering Department, College of Engineering, Al Imam Mohammad Ibn Saud Islamic University, Riyadh 11432, Saudi Arabia
| | - Djamel Ghernaout
- Chemical Engineering Department, College of Engineering, University of Ha’il, P.O. Box 2440, Ha’il 81441, Saudi Arabia; (N.E.); (D.G.); (S.G.)
- Chemical Engineering Department, Faculty of Engineering, University of Blida, P.O. Box 270, Blida 09000, Algeria
| | - Saad Ghareba
- Chemical Engineering Department, College of Engineering, University of Ha’il, P.O. Box 2440, Ha’il 81441, Saudi Arabia; (N.E.); (D.G.); (S.G.)
- Department of Chemical and Petroleum Engineering, ElMergib University, Alkhums 40414, Libya
| | - Majeda Khraisheh
- Department of Chemical Engineering, College of Engineering, Qatar University, Doha 2713, Qatar;
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Chang PH, Lee YT, Peng CH. Synthesis and Characterization of Hybrid Metal Zeolitic Imidazolate Framework Membrane for Efficient H 2/CO 2 Gas Separation. Materials (Basel) 2020; 13:ma13215009. [PMID: 33172108 PMCID: PMC7664411 DOI: 10.3390/ma13215009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 11/26/2022]
Abstract
In this paper, we propose mixed metal ions in the node of the zeolitic imidazolate framework (ZIF) structure. The hybrid metal ZIF is formed for the gas separation of hydrogen and carbon dioxide. In the first stage, the nanoparticles were prepared as a coating on a substrate, and acting as secondary growing nuclei. The hybrid metal ZIF structures were characterized by X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). N2 adsorption–desorption isotherms determined surface area, and scanning electron microscopy (SEM) was used to observe the microstructure and surface morphology. The hybrid metal ZIF-8-67 powder had the largest surface area (1260.40 m2 g−1), and the nanoparticles (100 nm) could be fully dense-coated on the substrate to benefit the subsequent membrane growth. In the second stage, we prepared the hybrid metal ZIF-8-67 membrane on the pre-seeding substrate with mixed metal nanoparticles of cobalt and zinc, by the microwave hydrothermal method. Cobalt ions were identified in the tetrahedral coordination through UV–Vis, and the membrane structure and morphology were determined by XRD and SEM. Finally, a gas permeation analyzer (GPA) was used to determine the gas separation performance of the hybrid metal ZIF-8-67 membrane. We successfully introduced zinc ions and cobalt ions into the ZIF structure, where cobalt had a strong interaction with CO2. Therefore, GPA analysis showed an excellent H2/CO2 separation factor due to lower CO2 permeability. The CO2 permeance was ~0.65 × 10−8 mol m−2 s−1 Pa−1, and the separation factors for H2/CO2 and H2/N2 were 9.2 and 2.9, respectively. Our results demonstrate that the hybrid metal ZIF-8-67 membrane has a superior H2/CO2 separation factor, which can be attributed to its very high specific surface area and structure. Based on the above, hybrid metal ZIF-8-67 membranes are expected to be applied in hydrogen or carbon dioxide gas separation and purification.
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Affiliation(s)
- Po-Hsueh Chang
- Department and Institute of Chemical and Materials Engineering, Minghsin University of Science and Technology, Xinxing Road, Hsinchu 30401, Taiwan;
| | - Yuan-Tse Lee
- Department of Materials Science and Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan;
| | - Cheng-Hsiung Peng
- Department and Institute of Chemical and Materials Engineering, Minghsin University of Science and Technology, Xinxing Road, Hsinchu 30401, Taiwan;
- Correspondence: ; Tel.: +8863-5593142 (ext. 2119)
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Upadhyaya L, Chiao YH, Wickramasinghe SR, Qian X. Cu(I/II) Metal-Organic Frameworks Incorporated Nanofiltration Membranes for Organic Solvent Separation. Membranes (Basel) 2020; 10:E313. [PMID: 33138087 DOI: 10.3390/membranes10110313] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 11/18/2022]
Abstract
Copper-based metal–organic frameworks (MOFs) with different oxidation states and near-uniform particle sizes have been successfully synthesized. Mixed-matrix polyimide membranes incorporating 0.1–7 wt% of Cu(II) benzene-1,2,5-tricarboxylic acid (Cu(II)BTC), Cu(I/II)BTC and Cu(I) 1,2-ethanedisulfonic acid (EDS) (Cu(I)EDS) MOFs were fabricated via non-solvent-induced phase inversion process. These membranes are found to be solvent resistant and mechanically stable. Liquid phase nanofiltration experiments were performed to separate toluene from n-heptane at room temperature. These membranes demonstrate preferential adsorption and permeation of the aromatic toluene over aliphatic n-heptane. The amount of MOF particles incorporated, the oxidation state of the Cu ion and membrane, and barrier layer thickness have a significant impact on the separation factor. Toluene/heptane separation factor at 1.47, 1.67 and 1.79 can be obtained for membranes incorporating 7 wt% Cu(II)BTC, Cu(I/II)BTC and Cu(I)EDS respectively at room temperature.
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ACAR S, CENGİZ HY, ERGÜN A, KONYALI E, DELİGÖZ H. A comparative study on the monovalent and divalent cation separation of polymeric films and membranes from salt solutions under diffusion-dialysis. Turk J Chem 2020; 44:1134-1147. [PMID: 33488218 PMCID: PMC7751909 DOI: 10.3906/kim-2004-26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 06/26/2020] [Indexed: 11/11/2022] Open
Abstract
This study deals with selective separation of mono- and divalent cations from aqueous salt solutions using polymeric films based on polyethylene (PE) and polyamide6 (PA6), and two different commercial nanofiltration (NF) membranes. The diffusion rates (D) of ions (Na+ and Ca2+), separation factors (α) and ion rejections (R) of the films and NF membranes are examined comparatively as well as their surface morphology and hydrophilicity. It is observed that the diffusion rates of Na+ are in the range of 0.7-1.8 × 10-8cm2 .s-1 in the decreasing order of PE > NF90 > NF270 > PA6 while Ca2+ shows diffusion rates of 7.4-18.4 × 10-8 cm2 .s-1 in the increasing order of NF270 > NF90 ≈ PA6 > PE. Rejection values of the polymeric films and NF membranes against to Na+ and Ca2+ vary between 90% and 99.6%.The highest α(Ca2+/Na+) is found to be 20 for PA6 film. D, α, and R value of both polymeric films and NF membranes are strongly affected by the existence of osmosis during diffusion-dialysis and the sizes of hydrated sodiu and calcium ions. In conclusion, the film based on PA6 may be a good alternative for selective separation of mono- an divalent cations.
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Affiliation(s)
- Serkan ACAR
- Department of Chemical Engineering, Engineering Faculty, İstanbul University-Cerrahpaşa, İstanbulTurkey
| | - Hacer Yeşim CENGİZ
- Department of Chemical Engineering, Engineering Faculty, İstanbul University-Cerrahpaşa, İstanbulTurkey
| | - Ayça ERGÜN
- Department of Chemical Engineering, Engineering Faculty, İstanbul University-Cerrahpaşa, İstanbulTurkey
| | - Eymen KONYALI
- Department of Chemical Engineering, Engineering Faculty, İstanbul University-Cerrahpaşa, İstanbulTurkey
| | - Hüseyin DELİGÖZ
- Department of Chemical Engineering, Engineering Faculty, İstanbul University-Cerrahpaşa, İstanbulTurkey
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Tsutsui N, Ban Y, Suzuki H, Nakase M, Ito S, Inaba Y, Matsumura T, Takeshita K. Effects of Diluents on the Separation of Minor Actinides from Lanthanides with Tetradodecyl-1,10-phenanthroline-2,9-diamide from Nitric Acid Medium. ANAL SCI 2020; 36:241-245. [PMID: 31564678 DOI: 10.2116/analsci.19p275] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/19/2019] [Indexed: 08/09/2023]
Abstract
To investigate the effective separation of actinides (Ans) from lanthanides (Lns), single-stage batch extraction experiments were performed with a novel extractant, tetradodecyl-1,10-phenanthroline-2,9-diamide (TDdPTDA) with various diluents such as 3-nitrobenzotrifluoride (F-3), nitrobenzene, and n-dodecane for Am, Cm, and Lns. The extraction kinetics with TDdPTDA was rapid enough to perform continuous extraction experiments using mixer-settler extractors. The slopes of the distribution ratio versus the TDdPTDA concentration and the distribution ratio versus the nitric acid concentration were similar for F-3 and nitrobenzene systems, but different from the n-dodecane system. These differences were attributed to the characteristics of the diluents. This study revealed high distribution ratios of Am (DAm) and Cm (DCm) for TDdPTDA, with the high separation factors (SFs) of Am from Lns enough for their separation.
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Affiliation(s)
- Nao Tsutsui
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1-16 Ookayama, Meguro, Tokyo, 152-8550, Japan.
- Research Group for Partitioning, Japan Atomic Energy Agency, 2-4 Sirakata, Tokai, Ibaraki, 319-1195, Japan.
| | - Yasutoshi Ban
- Research Group for Partitioning, Japan Atomic Energy Agency, 2-4 Sirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Hideya Suzuki
- Research Group for Partitioning, Japan Atomic Energy Agency, 2-4 Sirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Masahiko Nakase
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1-16 Ookayama, Meguro, Tokyo, 152-8550, Japan
| | - Sayumi Ito
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1-16 Ookayama, Meguro, Tokyo, 152-8550, Japan
| | - Yusuke Inaba
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1-16 Ookayama, Meguro, Tokyo, 152-8550, Japan
| | - Tatsuro Matsumura
- Research Group for Partitioning, Japan Atomic Energy Agency, 2-4 Sirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Kenji Takeshita
- Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1-N1-16 Ookayama, Meguro, Tokyo, 152-8550, Japan
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Oi T, Seki K, Kikawada Y, Yanase S. Observation of 18O/ 16O isotope effects at the cathode of a polymer electrolyte membrane fuel cell. Isotopes Environ Health Stud 2019; 55:199-210. [PMID: 30744417 DOI: 10.1080/10256016.2019.1575826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
18O/16O isotope effects were observed at the cathode of a polymer electrolyte membrane fuel cell at 25 and 35°C. Results of experiments in which the 18O/16O isotope ratios of the oxygen gases supplied to and exhausted from the cell were measured revealed that the lighter isotope 16O reacted more preferentially to form water molecules at the cathode than the heavier one, 18O. The value of the oxygen isotope separation factor, S1, defined as the ratio of the 18O/16O isotope ratios of the oxygen gases supplied to and exhausted from the cell, ranged from 1.0030 to 1.0139, and tended to decrease with decreasing rate of oxygen utilisation (θ) and with increasing flow rate of the feed oxygen gas (DF). The value of another separation factor, S2, defined as the ratio of the 18O/16O isotope ratios of the exhausted oxygen gas and oxygen having reacted to form water molecules at the cathode, ranged from 1.0049 to 1.0304. The S2 value was much less affected by the change in θ and DF than the S1 value with the majority of the S2 value being in the range of 1.0240-1.0304.
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Affiliation(s)
- Takao Oi
- a Faculty of Science and Technology , Sophia University , Tokyo , Japan
| | - Kaishu Seki
- a Faculty of Science and Technology , Sophia University , Tokyo , Japan
| | | | - Satoshi Yanase
- a Faculty of Science and Technology , Sophia University , Tokyo , Japan
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