Water content, relative permittivity, and ion sorption properties of polymers for membrane desalination

Chang, Kevin; Luo, H.; Geise, Geoffrey M.

doi:10.1016/j.memsci.2018.12.048

Cited by 41 publications

(104 citation statements)

References 76 publications

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“…In Equation 14, the permittivity of a hydrated membrane ( ) can either be measured experimentally [48][49][50], or alternatively be approximated by the following additive rule [25]:…”

Section: Calculation Of the Counter-ion Activity Coefficientmentioning

confidence: 99%

“…According to Equation 14, the Manning parameter (ξ) can be calculated when the b values and the permittivity of hydrated membranes (𝜀) are known. The values of 𝜀 can be measured experimentally [48][49][50] or alternatively can be approximated with the average of the membrane polymer and the water permittivity (Equation 16). Table 5 lists the approximated 𝜀 values, Bjerrum length (𝜆 G ) and ξ values for the three types of CEMs.…”

Section: The Manning Parameter and Cation Activity Coefficientsmentioning

confidence: 99%

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Combining Manning's theory and the ionic conductivity experimental approach to characterize selectivity of cation exchange membranes

Luo

Zhong

et al. 2021

Journal of Membrane Science

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The transport selectivity of different cations through cation exchange membranes (CEMs) could be estimated with the partition coefficient (𝐾 ! " ) and the cation mobility ratio in the membrane (𝑢 # " 𝑢 # ! ⁄ ), which in turn can be related to corresponding membrane conductivity and dimensional swelling degree data [Journal of Membrane Science, 2020, 597, 117645]. This method has been validated in two hydrocarbon-based CEMs, and the obtained K + /Na + selectivity equals to the one obtained with conventional electrodialysis (ED) method. However, the K + /Na + selectivity of perfluorosulfonic acid (PFSA) membranes, and the bi-/monovalent cation (Mg 2+ /Na + ) selectivity of all three types of CEMs estimated with this ionic conductivity experimental approach deviate noticeably from corresponding values obtained with ED. In this work, it is proved that this deviation is mostly due to the simplification of cation activity coefficients in the membrane. Here, the cation activity coefficients in three types of CEMs are calculated according to Manning`s counter-ion condensation model. In this model, the Manning parameter (𝜉) characterizing the dimensionless linear charge density is determined by the

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“…In Equation 14, the permittivity of a hydrated membrane ( ) can either be measured experimentally [48][49][50], or alternatively be approximated by the following additive rule [25]:…”

Section: Calculation Of the Counter-ion Activity Coefficientmentioning

confidence: 99%

Section: The Manning Parameter and Cation Activity Coefficientsmentioning

confidence: 99%

Combining Manning's theory and the ionic conductivity experimental approach to characterize selectivity of cation exchange membranes

Luo

Zhong

et al. 2021

Journal of Membrane Science

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“…In addition, the air bubbles had a greater effect on the relative permittivity than the adhesion performances. According to previous studies, it has been reported that the relative permittivity of polymer can vary greatly depending on the air gap [ 38 , 39 , 40 ].…”

Section: Resultsmentioning

confidence: 99%

Free Volume Effect via Various Chemical Structured Monomers on Adhesion Property and Relative Permittivity in Acrylic Pressure Sensitive Adhesives

Lee

Kim

et al. 2020

Polymers

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Acrylic pressure-sensitive adhesives (PSAs) are used as fixatives between layers of a display. PSAs’ function is an important factor that determines the performance of the display. Of the various display types available, the touch screen panel (TSP) of smart devices is firmly related to the relative permittivity of the elementals. Therefore, adjusting the relative permittivity of the PSA is indispensable for driving the TSP. Accordingly, selected acrylic pre-polymers were polymerized and the pre-polymer was blended and cross-linked with monomers with different chemical structure to adjust the relative permittivity. The monomers were hexametyldisiloxane (HMDS), N-vinylcaprolactam (NVC), tert-butyl acrylate (TBA), and isooctadecyl acrylate (ISTA). The gel fraction and transmittance as a function of the monomers show a similar result to the pure acrylic PSA. However, the gel fraction value decreased to about 90% and the transmittance decreased to about 85%, due to the immiscibility between nonpolar HMDS and acrylic PSA. On the other hand, the adhesion properties were improved when NVC was added because of the polarity of the nitrogen group. In addition, the relative permittivity of the PSA decreased regardless of the monomer chosen. There was, however, a difference in the optimal content of each monomer, and NVC decreased from 4 phr content to about 3.4 in reducing relative permittivity. Through the above results, it was confirmed that NVC having a nitrogen group is most advantageous in lowering adhesion properties and relative permittivity, and necessitates further research based on the findings.

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“…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,…”

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%

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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Water content, relative permittivity, and ion sorption properties of polymers for membrane desalination

Cited by 41 publications

References 76 publications

Combining Manning's theory and the ionic conductivity experimental approach to characterize selectivity of cation exchange membranes

Combining Manning's theory and the ionic conductivity experimental approach to characterize selectivity of cation exchange membranes

Free Volume Effect via Various Chemical Structured Monomers on Adhesion Property and Relative Permittivity in Acrylic Pressure Sensitive Adhesives

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

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