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Pakalniete LD, Maskova E, Zabolockis RJ, Avotina L, Sprugis E, Reinholds I, Rzepna M, Vaivars G, Pajuste E. Critical Evaluation of the Methods for the Characterization of the Degree of Sulfonation for Electron Beam Irradiated and Non-Irradiated Sulfonated Poly(ether ether ketone) Membranes. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6098. [PMID: 37763376 PMCID: PMC10532506 DOI: 10.3390/ma16186098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/24/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
Sulfonated poly(ether ether ketone) (SPEEK) materials are promising candidates for replacing Nafion™ in applications such as proton exchange membrane (PEM) and direct methanol fuel cells. SPEEK membranes have several advantages such as low cost, thermal and radiation stability and controllable physicochemical and mechanical properties, which depend on the degree of sulfonation (DS). Commercial PEEK was homogenously sulfonated up to a DS of 60-90% and the membranes were prepared using a solvent casting method. Part of the samples were irradiated with a 10 MeV electron beam up to a 500 kGy dose to assess the ionizing radiation-induced effects. Both non-irradiated and irradiated membranes were characterized by Fourier Transformation infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), proton nuclear magnetic resonance (1H-NMR) spectroscopy, electrochemical impedance analysis and, for the first time for non-irradiated membranes, by spectrophotometric analysis with Cr(III). The above-mentioned methods for application for DS assessment were compared. The aim of this study is to compare different methods used for the determination of the DS of SPEEK membranes before and after high-dose irradiation. It was observed that irradiated membranes presented a higher value of DS. The appearance of different new signals in 1H-NMR and FT-IR spectra of irradiated membranes indicated that the effects of radiation induced changes in the structure of SPEEK materials. The good correlation of Cr(III) absorption and SPEEK DS up to 80% indicates that the spectrophotometric method is a comparable tool for the characterization of SPEEK membranes.
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Affiliation(s)
- Laura Dace Pakalniete
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
- Faculty of Chemistry, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia;
| | - Elizabete Maskova
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
- Faculty of Chemistry, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia;
| | - Rudolfs Janis Zabolockis
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
- Faculty of Chemistry, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia;
| | - Liga Avotina
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
| | - Einars Sprugis
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
- Institute of Solid State Physics, University of Latvia, Kengaraga Iela 8, LV-1063 Riga, Latvia
| | - Ingars Reinholds
- Faculty of Chemistry, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia;
- Baltic Scientific Instruments, Ganibu Dambis 26, LV-1005 Riga, Latvia
- Institute of Food Safety, Animal Health and Environment “BIOR”, Lejupes Iela 3, LV-1076 Riga, Latvia
| | - Magdalena Rzepna
- Centre for Radiation Research and Technology, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland;
| | - Guntars Vaivars
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
- Faculty of Chemistry, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia;
- Institute of Solid State Physics, University of Latvia, Kengaraga Iela 8, LV-1063 Riga, Latvia
| | - Elina Pajuste
- Institute of Chemical Physics, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia; (L.D.P.); (L.A.); (E.S.); (G.V.); (E.P.)
- Faculty of Chemistry, University of Latvia, Jelgavas Iela 1, LV-1004 Riga, Latvia;
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Xue X, Chu X, Zhang M, Wei F, Liang C, Liang J, Li J, Cheng W, Deng K, Liu W. High Hydrogen Isotope Separation Efficiency: Graphene or Catalyst? ACS APPLIED MATERIALS & INTERFACES 2022; 14:32360-32368. [PMID: 35792902 DOI: 10.1021/acsami.2c06394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Single-layer graphene has been demonstrated to be a high-efficiency hydrogen isotope sieving membrane in the electrochemical hydrogen pumping system. In this work, we transferred this membrane to proton exchange membrane water electrolysis (PEMWE), which has wide industrial applications. Two membrane electrode assemblies with decorated Pt and ink-coated Pt were investigated. The graphene with the decorated Pt scheme acquired the reported highest proton-to-tritium separation factor of 19.50 in PEMWE. However, rather than graphene, the decorated catalyst was demonstrated to be responsible for this remarkable separation efficiency. Previous studies from Geim's group underestimated the enhanced separation efficiency of decorated Pt over ink-coated Pt, resulting in an exaggerated separation efficiency for graphene. The behavior of proton transfer with hydrogen isotope separation through graphene was interpreted by a serial-parallel circuit model, which suggested that hydrogen isotope separation occurs at defect sites. The limited separation efficiency for graphene was also well understood by a density functional theory (DFT) calculation using an SW 55-77 model and the transition state theory for the kinetic isotope effect. This research provides a thorough understanding of proton transfer with hydrogen isotope separation through graphene.
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Affiliation(s)
- Xiaochong Xue
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - XinXin Chu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Mingjun Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Wei
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaofei Liang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Liang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinglin Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenyu Cheng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ke Deng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Wei Liu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Copia L, Wassenaar LI, Terzer-Wassmuth S, Belachew DL, Araguas-Araguas LJ. Comparative evaluation of 2H- versus 3H-based enrichment factor determination on the uncertainty and accuracy of low-level tritium analyses of environmental waters. Appl Radiat Isot 2021; 176:109850. [PMID: 34246163 DOI: 10.1016/j.apradiso.2021.109850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 05/26/2021] [Accepted: 06/28/2021] [Indexed: 10/21/2022]
Abstract
Analysis of low-level tritium (3H) in environmental waters requires pre-concentration using electrolytic enrichment prior to decay counting. Accurate and precise electrolytic enrichment factors (EF) are required to determine the sample's environmental 3H concentration. Two methods are used to determine EFs: i) the Spike Proxy Method (SPM) and ii) the Deuterium Method (DM) with each having several modalities. We conducted a comparative assessment of four EF strategies using 250 mL and 500 mL electrolytic enrichment of three low-level 3H proficiency water standards (0.5-7 TU) to see which strategy gave the most accurate 3H results based on z- and Zeta-scores. Our comparative evaluation revealed the DM offers consistently superior 3H results, with more precise EF determinations compared to the three SPM strategies. The DM gave the best z-scores with an EF relative combined uncertainty of about 0.5‰ and a negligible contribution to the overall uncertainty budget due to the EF determination. Moreover, the DM can improve productivity by eliminating the spike and gravimetric procedures from routine analyses and can give rapid cell enrichment performance feedback prior to decay counting. We recommend low-level tritium laboratories consider adopting the DM into their 3H sample enrichment and analysis operations.
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Affiliation(s)
- Lorenzo Copia
- International Atomic Energy Agency, Vienna International Center, A-1400, Vienna, Austria.
| | - Leonard I Wassenaar
- International Atomic Energy Agency, Vienna International Center, A-1400, Vienna, Austria
| | - Stefan Terzer-Wassmuth
- International Atomic Energy Agency, Vienna International Center, A-1400, Vienna, Austria
| | - Dagnachew L Belachew
- International Atomic Energy Agency, Vienna International Center, A-1400, Vienna, Austria
| | - Luis J Araguas-Araguas
- International Atomic Energy Agency, Vienna International Center, A-1400, Vienna, Austria
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Copia L, Wassenaar LI, Terzer-Wassmuth S, Hillegonds DJ, Klaus PM, Araguás-Araguás LJ. Proficiency testing of 78 international laboratories measuring tritium in environmental waters by decay counting and mass spectrometry for age dating and water resources assessment. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8832. [PMID: 32415697 DOI: 10.1002/rcm.8832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE Tritium (3 H) is an important hydrological tracer that has been commonly used for over 60 years to evaluate water residence times and water dynamics in shallow/recent groundwaters, streams, lakes and the ocean. We tested the analytical performance of 78 international laboratories engaged in low-level 3 H assays for water age dating and monitoring of environmental waters. METHODS Seven test waters were distributed by the IAEA to 78 international tritium laboratories. Set 1 included a tritium-free groundwater plus three ultra-low 3 H samples (0.5-7 TU) for meeting groundwater dating specifications. Set 2 contained three higher 3 H-content samples (40-500 TU) suitable for testing of environmental monitoring laboratories. RESULTS Seventy of the laboratories used liquid scintillation counting with or without electrolytic enrichment, seven utilized 3 He accumulation and mass spectrometry, and one used gas-proportional counting. Only ~50% of laboratories demonstrated the ability to generate accurate 3 H data that was precise enough for water age dating purposes. CONCLUSIONS The proficiency test helped identify recurrent weaknesses and potential solutions. Strategies for performance improvements of 3 H laboratories include: (a) improved quantification of 3 H detection limits and analytical uncertainty, (b) stricter quality control practices in routine operations along with care and recalibration of 3 H standards traceable to primary NIST standards, (c) annual assessment of tritium enrichment factors and instrumental performance, and (d) for water age dating purposes the use of electrolytic enrichment systems having the highest possible 3 H enrichment factors (e.g. >50×).
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Affiliation(s)
- Lorenzo Copia
- International Atomic Energy Agency, Vienna International Centre, Vienna, A-1400, Austria
| | - Leonard I Wassenaar
- International Atomic Energy Agency, Vienna International Centre, Vienna, A-1400, Austria
| | - Stefan Terzer-Wassmuth
- International Atomic Energy Agency, Vienna International Centre, Vienna, A-1400, Austria
| | - Darren J Hillegonds
- Department of Earth Sciences, South Parks Road, University of Oxford, Oxford, OX1 3AN, UK
| | - Philipp M Klaus
- International Atomic Energy Agency, Vienna International Centre, Vienna, A-1400, Austria
| | - Luis J Araguás-Araguás
- International Atomic Energy Agency, Vienna International Centre, Vienna, A-1400, Austria
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