Multicomponent transport of alcohols in Nafion 117 measured by in situ ATR FTIR spectroscopy

Dobyns, Breanna M.; Kim, Jung Min; Li, Jing; Jiang, Zhihua; Beckingham, Bryan S.

doi:10.1016/j.polymer.2020.123046

Cited by 13 publications

(23 citation statements)

References 57 publications

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“…Generally, EtOH solubilities are higher than those of salt solubilities by 1.7 times, on average, indicating that EtOH uptake is preferred in these films ( ϕ w : 0.2–0.5) over the uptake of carboxylate salts. We observed similar behavior in a previous investigation of cation exchange membranes (CEM) [ 29 , 32 , 50 ], where the alcohol (MeOH and EtOH) solubilities were higher than the carboxylate (NaOFm and NaOAc) solubilities. However, contrary to our previous investigations of CEMs, the EtOH concentrations in the AEMs here (A0, A8, A12 and AMVN) after sorption in the external solution (1 M EtOH) were less than those of the external solution, such that EtOH is less preferred in these films over the external solution; see Supporting Information Table S8 .…”

Section: Resultssupporting

confidence: 87%

“…where P i is the permeability to solute i, D i is the diffusivity to solute i, and K i is the solubility to solute i, for EtOH [8,50] or a carboxylate anion (OFm − or OAc − [51,52]) in single and co-transport between EtOH and a carboxylate (EtOH-KOFm, EtOH-KOAc, EtOH-NaOFm and EtOH-NaOAc. The multi-solute permeability measurement was enabled by our in situ ATR-FTIR probe approach, which we recently devised [29].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, we measure carboxylate permeability (in co-diffusion) and solubility (from a mixture) with ethanol (EtOH). We then calculate diffusivities ( D i ) to OFm − and OAc − in both K + and Na + forms (KOFm, KOAc, NaOFm and NaOAc) using the solution-diffusion model (Equation (1)) [ 39 ], which describes the overall solute permeation, which is dependent on solute sorption [ 22 , 40 , 41 , 42 , 43 ] into the membrane and diffusion [ 18 , 42 , 44 , 45 ] through the fractional free volume [ 46 , 47 , 48 , 49 ] within the polymer matrix, P i = D i K i , where

is the permeability to solute i ,

is the diffusivity to solute i , and

is the solubility to solute i , for EtOH [ 8 , 50 ] or a carboxylate anion (OFm − or OAc − [ 51 , 52 ]) in single and co-transport between EtOH and a carboxylate (EtOH-KOFm, EtOH-KOAc, EtOH-NaOFm and EtOH-NaOAc. The multi-solute permeability measurement was enabled by our in situ ATR–FTIR probe approach, which we recently devised [ 29 ].…”

Section: Introductionmentioning

confidence: 99%

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Transport and Co-Transport of Carboxylate Ions and Ethanol in Anion Exchange Membranes

et al. 2021

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Understanding multi-component transport behavior through hydrated dense membranes is of interest for numerous applications. For the particular case of photoelectrochemical CO2 reduction cells, it is important to understand the multi-component transport behavior of CO2 electrochemical reduction products including mobile formate, acetate and ethanol in the ion exchange membranes as one role of the membrane in these devices is to minimize the permeation of these products. Anion exchange membranes (AEM) have been employed in these and other electrochemical devices as they act to facilitate the transport of common electrolytes (i.e., bicarbonates). However, as they act to facilitate the transport of carboxylates as well, thereby reducing the overall performance, the design of new AEMs is necessary to improve device performance through the selective transport of the desired ion(s) or electrolyte(s). Here, we investigate the transport behavior of formate and acetate and their co-transport with ethanol in two types of AEMs: (1) a crosslinked AEM prepared by free-radical copolymerization of a monomer with a quaternary ammonium (QA) group and a crosslinker, and (2) Selemion® AMVN. We observe a decrease in diffusivities to carboxylates in co-diffusion. We attribute this behavior to charge screening by the co-diffusing alcohol, which reduces the electrostatic attraction between QAs and carboxylates.

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

is the permeability to solute i ,

is the diffusivity to solute i , and

Section: Introductionmentioning

confidence: 99%

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Transport and Co-Transport of Carboxylate Ions and Ethanol in Anion Exchange Membranes

et al. 2021

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“…Previously, our group has performed a series of investigations to gain a fundamental understanding of the cotransport behavior of an alcohol (MeOH) and a carboxylate anion (either OFm À or OAc À ) in CEMs (with bound sulfonate). 13,15,17 In Nafion ® 117, we observed increases in both OFm À and OAc À permeability in co-permeation with MeOH, where we conjectured that electrostatic repulsions between bound sulfonate and mobile carboxylate ions might be interfered with by the co-permeating MeOH molecules. 13 Next, we prepared a series of chargeneutral crosslinked poly(ethylene glycol) diacrylate (PEGDA, n = 13, where n represents the number of ethylene oxide repeating units [18][19][20][21][22][23] ) films at varied fractional free volume (FFV), where we observed OAc À permeability increases in co-permeation with MeOH and that the differences between permeability in single solute and co-permeation increased with increasing FFV.…”

Section: Introductionmentioning

confidence: 72%

“…5,6 Traditionally, IEM design for PEC-CRC has been focused on anion exchange membranes (AEM [9][10][11][12] ) as they show higher diffusibility for negatively-charged electrolytes, such as bicarbonates. However, CEMs [13][14][15][16] can be advantageous as they can minimize the permeation of negatively-charged CO 2 reduction products, such as OFm À and OAc À . Previously, our group has performed a series of investigations to gain a fundamental understanding of the cotransport behavior of an alcohol (MeOH) and a carboxylate anion (either OFm À or OAc À ) in CEMs (with bound sulfonate).…”

Section: Introductionmentioning

confidence: 99%

Transport and co‐transport of carboxylate ions and alcohols in cation exchange membranes

Kim

Beckingham

2021

Journal of Polymer Science

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Understanding multi‐component transport behavior through hydrated dense membranes is of interest for numerous applications. For the particular case of photoelectrochemical CO2 reduction cells (PEC‐CRC), it is important to understand the multi‐component transport behavior of CO2 electrochemical reduction products including mobile carboxylates (formate and acetate) and alcohols (methanol and ethanol) in the ion exchange membranes as one role of the membrane in these devices is to minimize the permeation of these CO2 reduction products to the anolyte as they often oxidize back to CO2. Cation exchange membranes (CEM) are promising candidates for such devices as they act to minimize the permeation of mobile anions, such as carboxylates. However, the design of new CEMs is necessary as the permeation of carboxylates often increases in co‐permeation with alcohols. Here, we investigate the transport behavior of carboxylates and alcohols in two types of CEMs (1) a crosslinked CEM was prepared by free‐radical copolymerization of a sulfonated monomer (AMPS) with a crosslinker (PEGDA), and (2) Nafion® 117. We observe an increase in both PEGDA‐AMPS and Nafion® 117 diffusivities to carboxylates in co‐diffusion with alcohols. We attribute this behavior to charge screening by co‐diffusing alcohol that reduces the electrostatic repulsion between bound sulfonates and mobile carboxylates.

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Quantification of Organic Solvent Concentration Profiles in Ion Exchange Membranes Via Confocal Raman Microscopy

Götz,

Komma,

Dworschak

et al. 2023

Adv Materials Inter

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The perfluorinated sulfonic acid membranes used in direct alcohol fuel cells cause low faradaic efficiency and performance due to alcohol absorption and permeation. Thus, a measurement setup is sought that enables a direct evaluation of the suitability of polymer electrolytes for this application. A 3D‐printed diffusion cell setup capable of measuring the interaction between the organic solvents, such as alcohols, and a proton exchange membrane via confocal Raman microscopy is introduced. The cell design employs flow channels to mimic the flow fields of electrochemical cell tests. Exemplarily, information on the interaction of membranes like Nafion 212 and the composite membrane Nafion XL with 1 m solutions of organic solvents such as 2‐propanol, acetone, and ethanol are provided to demonstrate the applicability of this setup. The Raman diffusion cell is capable of quantifying the preferred solvent uptake, which is characterized by the sorption coefficient, the permeability, and the concentration gradient within the membrane. These properties can be obtained in situ and in a time‐resolved manner. Thus, this diffusion cell setup is a powerful and accessible tool for screening membrane compatibility with various liquids.

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Multicomponent transport of alcohols in Nafion 117 measured by in situ ATR FTIR spectroscopy

Cited by 13 publications

References 57 publications

Transport and Co-Transport of Carboxylate Ions and Ethanol in Anion Exchange Membranes

Transport and Co-Transport of Carboxylate Ions and Ethanol in Anion Exchange Membranes

Transport and co‐transport of carboxylate ions and alcohols in cation exchange membranes

Quantification of Organic Solvent Concentration Profiles in Ion Exchange Membranes Via Confocal Raman Microscopy

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