Nonlinearly induced electro-osmotic flow reversal in charged nanotube: Counter-ions mobility in Stern layer

Wang, Yu; Liu, Runkeng; Liu, Zhenyu

doi:10.1016/j.ijheatmasstransfer.2022.122587

Cited by 8 publications

(4 citation statements)

References 35 publications

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“…The diffusive layer region consists of dissociated water ions that are loosely attracted to the biomass surface. 159 Existing dewatering processes using membranes often employ a mechanical force (e.g., pressure), inducing liquid water to permeate the membrane. 160 However, this mechanical force is nonspecific and is imposed on all species in the feed mixture, ultimately resulting in movement of all species in the slurry.…”

Section: Electrically Assisted Membrane Dewateringmentioning

confidence: 99%

“…Adjacent to the EDL lies the diffusive layer that extends into the bulk aqueous medium. The diffusive layer region consists of dissociated water ions that are loosely attracted to the biomass surface …”

Section: Advances In Membrane Dewateringmentioning

confidence: 99%

“…The diffusive layer region consists of dissociated water ions that are loosely attracted to the biomass surface. 159 …”

Section: Advances In Membrane Dewateringmentioning

confidence: 99%

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Advances in Membrane Separation for Biomaterial Dewatering

Diepenbroek,

Mehta,

Borneman

et al. 2024

Langmuir

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Biomaterials often contain large quantities of water (50−98%), and with the current transition to a more biobased economy, drying these materials will become increasingly important. Contrary to the standard, thermodynamically inefficient chemical and thermal drying methods, dewatering by membrane separation will provide a sustainable and efficient alternative. However, biomaterials can easily foul membrane surfaces, which is detrimental to the performance of current membrane separations. Improving the antifouling properties of such membranes is a key challenge. Other recent research has been dedicated to enhancing the permeate flux and selectivity. In this review, we present a comprehensive overview of the design requirements for and recent advances in dewatering of biomaterials using membranes. These recent developments offer a viable solution to the challenges of fouling and suboptimal performances. We focus on two emerging development strategies, which are the use of electric-field-assisted dewatering and surface functionalizations, in particular with hydrogels. Our overview concludes with a critical mention of the remaining challenges and possible research directions within these subfields.

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Section: Electrically Assisted Membrane Dewateringmentioning

confidence: 99%

Section: Advances In Membrane Dewateringmentioning

confidence: 99%

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Advances in Membrane Separation for Biomaterial Dewatering

Diepenbroek,

Mehta,

Borneman

et al. 2024

Langmuir

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“…One of the important parameters to be managed for PFSA membranes is the electro-osmotic drag (EOD) coefficient. − It is defined as the ratio between the number of water molecules and protons transferred across the membrane in the absence of gradients in concentration and pressure and at vanishing electric field − , Here, ξ D is the EOD coefficient of water in the membrane, is the flux of water, and is the flux of protons across the membrane in the presence of the electric field. While the definition of the EOD coefficient is straightforward, many attempts have been made to rationalize and quantify this parameter using experiments and simulations. ,,,− As it will be discussed in this paper, the results of different experiments and simulation methods show a large scattering.…”

Section: Introductionmentioning

confidence: 99%

Electro-osmotic Drag and Thermodynamic Properties of Water in Hydrated Nafion Membranes from Molecular Dynamics

et al. 2022

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One of the important parameters in water management of proton exchange membranes is the electro-osmotic drag (EOD) coefficient of water. The value of the EOD coefficient is difficult to justify, and available literature data on this for Nafion membranes show scattering from in experiments and simulations. Here, we use a classical all-atom model to compute the EOD coefficient and thermodynamic properties of water from molecular dynamics simulations for temperatures between 330 and 420 K, and for different water contents between λ = 5 and λ = 20. λ is the ratio between the moles of water molecules to the moles of sulfonic acid sites. This classical model does not capture the Grotthuss mechanism; however, it is shown that it can predict the EOD coefficient within the range of experimental values for λ = 5 where the vehicular mechanism dominates proton transfer. For λ > 5, the Grotthuss mechanism becomes dominant. To obtain the EOD coefficient, average velocities of water and ions are computed by imposing different electric fields to the system. Our results show that the velocities of water and hydronium scale linearly with the electric field, resulting in a constant ratio of ca. 0.4 within the error bars. We find that the EOD coefficient of water linearly increases from 2 at λ = 5 to 8 at λ = 20 and the results are not sensitive to temperature. The EOD coefficient at λ = 5 is within the range of experimental values, confirming that the model can capture the vehicular transport of protons well. At λ = 20, due to the absence of proton hopping in the model, the EOD coefficient is overestimated by a factor of 3 compared to experimental values. To analyze the interactions between water and Nafion, the partial molar enthalpies and partial molar volumes of water are computed from molecular dynamics simulations. At different water uptakes, multiple linear regression is used on raw simulation data within a narrow composition range of water inside the Nafion membrane. The partial molar volumes and partial molar excess enthalpies of water asymptotically approach the molar volumes and molar excess enthalpies of pure water for water uptakes above 5. This confirms the model can capture the bulklike behavior of water in the Nafion at high water uptakes.

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Applied Electric Field Effects on Diffusivity and Electrical Double‐Layer Thickness

Masuduzzaman,

Bakli,

Barisik

et al. 2024

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This study utilizes molecular dynamics (MD) simulations and continuum frameworks to explore electroosmotic flow (EOF) in nanoconfined aqueous electrolytes, offering a promising alternative to conventional micro‐/nanofluidic systems. Although osmotic behavior in these environments is deeply linked to local fluid properties and interfacial dynamics between the fluid and electrolyte solutions, achieving a complete molecular‐level understanding has remained challenging. The findings establish a linear relationship between electric field strength and fluid velocity, uncovering two distinct transport regimes separated by a critical threshold, with a markedly intensified flow in the second regime. It is demonstrated that rising electric field strengths significantly enhance water diffusion coefficients, supported by a detailed analysis of fluid hydration structures, the potential of mean force (PMF), and local stress tensors. Due to the applied electric field strength, the motion of ions and water accelerates, leading to the redistribution of ions and intensification of electrostatic forces. This expands the thickness of the electric double layer (EDL) and amplifies fluid diffusivity, thereby enhancing nanoscale fluid activity. These insights enhance the molecular‐level understanding of EOF and define the stability of flow regimes, providing valuable guidelines for advancing nanofluidic technologies, such as drug delivery systems and lab‐on‐a‐chip devices.

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Nonlinearly induced electro-osmotic flow reversal in charged nanotube: Counter-ions mobility in Stern layer

Cited by 8 publications

References 35 publications

Advances in Membrane Separation for Biomaterial Dewatering

Advances in Membrane Separation for Biomaterial Dewatering

Electro-osmotic Drag and Thermodynamic Properties of Water in Hydrated Nafion Membranes from Molecular Dynamics

Applied Electric Field Effects on Diffusivity and Electrical Double‐Layer Thickness

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