Specifics of highly selective ammonia transport through gas-separating membranes based on perfluorinated copolymer in the form of hollow fibers

Timashev, S. F.; Vorobiev, A.V.; Kirichenko, V. I.; Popkov, Yu.M.; Volkov, V. I.; Shifrina, R.R.; Lyapunov, A. Ya.; Bondarenko, A. G.; Bobrova, L. P.

doi:10.1016/s0376-7388(00)81178-3

Cited by 32 publications

(14 citation statements)

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“…Also, the increase of cathode flowrate at the fixed anode flowrate induced an increase in the mole flux of ammonia through MEA or membrane to the cathode and reached steady state, which allowed us to obtain the diffusivity of NH 3 through MEA or membrane. Ex-situ mass-uptake method in N117 100% 2.6 ± 0.3 Â 10 À6 1.1 ± 0.2 Â 10 À5 D Naþ ¼ 5.0 ± 0.4 Â 10 À6 D Naþ ¼ 1.5 ± 0.2 Â 10 À5 Gas permeability measurement N/A 3.5 Â 10 À7 [22] Pulsed-field gradient nuclear magnetic resonance spectroscopy 100% D Naþ ¼ 1.03 Â 10 À6 [24] Nonstationary radiotracer diffusion method 100% D Liþ ¼ 1.4 Â 10 À6 [25] Radiotracer permeation 100% D Naþ ¼ 1.7 Â 10 À6 [26,27] Finally, the results showed that the transport of ammonia is governed by the combined mechanisms of diffusion-solubility and diffusion-reaction in the N 2 /N 2 system for RHs greater than 50%. Diffusion coefficients of NH 3 at T cell ¼ 80 C were also calculated at different values of RH (2.4 Â 10 À6 cm 2 s À1 at RH ¼ 50% and 3.4 Â 10 À6 cm 2 s À1 at RH ¼ 80%).…”

Section: Discussionmentioning

confidence: 99%

“…For these assumptions, the diffusion coefficients of ammonia at the different RHs (i.e., RH ¼ 50 and 80%) are listed in Table 2. Timashev et al [22] reported theD NH3 (i.e., 3.5 Â 10 À7 cm 2 s À1 ) obtained in PFSA polymer hollow-fibers at 23 C (not report humidity). The reported diffusion coefficient is 1-order lower than ours (i.e., 2.4 Â 10 À6 cm 2 s À1 at RH ¼ 50% and 3.4 Â 10 À6 cm 2 s À1 at RH ¼ 80%) and obtained at higher temperature (i.e., T ¼ 80 C).…”

Section: Transport Mechanism Of Ammonia In Membranementioning

confidence: 99%

“…Thus, NH 3 (g), NH 3 (m), and the NH 4 þ form are equilibrated throughout the MEA but a steady state is obtained which involves the diffusion of NH 3 through the MEA from the anode to the cathode, after all of the available proton sites have exchanged. The self diffusion of NH 4 þ ions can also be suggested, but the diffusion of molecules through the membrane after exchange is the limiting factor of NH 3 transport rather than NH 4 þ [22].…”

Section: Transport Mechanism Of Ammonia In Membranementioning

confidence: 99%

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An experimental approach to investigate the transport of ammonia as a fuel contaminant in proton exchange membrane fuel cells

Jung¹,

Cho

Park

et al. 2015

Journal of Power Sources

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h i g h l i g h t sThe data support a diffusion-solubility mechanism in a N 2 /N 2 system at OCV. Ammonia did not move across the membrane when the feed to both electrodes was dry. With humidified feeds, the ammonia was transported from the anode to the cathode. Diffusion coefficients of NH 3 at 80 C are obtained as~10 À6 cm 2 s À1 at RH ¼ 50 and 80%. a b s t r a c tData are presented for the transport of NH 3 from the anode to the cathode for various inlet conditions in a N 2 /N 2 laboratory-scale fuel cell at open circuit voltage (OCV). The data were obtained with a material balance technique, which uses an ion selective electrode (ISE) to determine the concentration of ammonium ions. The results show that ammonia did not move across the membrane when the feed to both electrodes was dry. However, with humidified feeds on either side, the ammonia was transported from the anode to the cathode. The data include changes in the relative humidity of the anode inlet and the flowrate on the cathode. The data support a diffusion-solubility mechanism in a N 2 /N 2 system at OCV.

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Section: Discussionmentioning

confidence: 99%

Section: Transport Mechanism Of Ammonia In Membranementioning

confidence: 99%

Section: Transport Mechanism Of Ammonia In Membranementioning

confidence: 99%

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An experimental approach to investigate the transport of ammonia as a fuel contaminant in proton exchange membrane fuel cells

Jung¹,

Cho

Park

et al. 2015

Journal of Power Sources

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“…However, in the case of active transfer, for example, for perfluorinated polymer membranes [20] or for membranes based on ionic liquids [21], the permeability of active penetrants, such as ammonia and carbon dioxide, increased due to the action of the facilitated transfer mechanism, namely, facilitated diffusion [22].…”

Section: Introductionmentioning

confidence: 99%

Effect of Moisture Presence on Gas Permeability through Gas Separation Membranes Based on Poly(Vinyltrimethylsilane) and Quaternized Chitosan

Otvagina

Atlaskin

Trubyanov

et al. 2020

Membr. Membr. Technol.

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An experimental evaluation of the humidity effect of gases (nitrogen, methane, and carbon dioxide) on their permeability through poly(vinyltrimethylsilane) and quaternized chitosan membranes using a specially designed experimental setup has been performed in this work. The experimental unit has been additionally equipped with a moisture generator and an analytical complex including an electronic hygrometer coupled with a gas chromatographic TCD system. The gas humidity values were obtained before and after the separation on polymeric membrane. It has been experimentally shown that the PVTMS membrane in the presence of water vapor (up to 2.5 vol %) provides the stability of gas transport characteristics. The permeability of moist gases through the quaternized chitosan membrane has been significantly reduced due to the high affinity of the polymer to water vapor and this material provides the high water vapor permeability.

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“…While the main application of Nafion as a cation‐selective membrane in the chlor‐alkali industrial process has been thoroughly studied,24 its function and properties in combination with ammonia, especially for analytical purposes, are less well known. Timashev et al 25 explain the high permeability of ammonia in a perfluorinated cation‐exchange membrane by transport through the pores in the polymer matrix by reversible reactions between ammonia and the sulfonate groups according to the equation: where R is the perfluorinated matrix. We assume that this mechanism can be utilized when sampling ammonia on a Nafion‐coated SPME fiber prior to nitrogen isotopic analysis.…”

mentioning

confidence: 99%

Nitrogen isotope analysis of ammonium in aqueous solutions using a perfluorosulfonated ionomer membrane for solid‐phase microextraction

Norlin

Irgum

Ohlsson

2003

Rapid Comm Mass Spectrometry

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The use of custom-made solid-phase microextraction (SPME) fibers coated with a perfluorosulfonated ionomer, Nafion, was investigated for nitrogen isotopic analysis of ammonium in aqueous solutions. Aqueous ammonium was converted to ammonia by addition of a base, followed by absorption from the headspace, desorption in the injection port of a gas chromatograph, and analysis by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Fibers coated with a Nafion tubing were chosen due to a higher fiber-gas distribution constant and a higher Nafion thickness than fibers coated with Nafion solution, both leading to a higher amount of ammonia absorbed at equilibrium. The Nafion membrane-coated fiber absorbed approximately 20 times more than a commercial polydimethylsiloxane (PDMS) fiber. The isotopic fractionation between fiber and gas was 1.0117 +/- 0.0009 (standard deviation, SD, of all measurements) at an initial ammonia gas concentration of 21-210 microM. At 390 microM initial gas concentration it was slightly lower. When sampling from liquid samples, an ammonium concentration of 10 mM was needed to obtain a sufficient amount of ammonia absorbed. Modeling of the absorption at different temperatures showed that the absorption was approximately constant in the temperature range suitable for SPME experiments. Absorption at room temperature was therefore used for simplicity. A pilot study was conducted in which absorption was achieved from a single 9 microL droplet of sample. The preliminary results showed that delta(15)N analysis was possible for only 0.4-0.5 micromol of ammonium with a SD of 0.8 per thousand (n = 5).

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Specifics of highly selective ammonia transport through gas-separating membranes based on perfluorinated copolymer in the form of hollow fibers

Cited by 32 publications

References 4 publications

An experimental approach to investigate the transport of ammonia as a fuel contaminant in proton exchange membrane fuel cells

An experimental approach to investigate the transport of ammonia as a fuel contaminant in proton exchange membrane fuel cells

Effect of Moisture Presence on Gas Permeability through Gas Separation Membranes Based on Poly(Vinyltrimethylsilane) and Quaternized Chitosan

Nitrogen isotope analysis of ammonium in aqueous solutions using a perfluorosulfonated ionomer membrane for solid‐phase microextraction

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