Equation of state of charged colloidal suspensions and its dependence on the thermodynamic route

Colla, Thiago; Santos, Alexandre Pereira dos; Levin, Yan

doi:10.1063/1.4718367

Cited by 22 publications

(20 citation statements)

References 64 publications

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“…and N f is the number of overlaps of the plates with the ions after a displacement ∆R that moves the two plates farther apart (superscript f stands for farther) 80 .…”

Section: Model and Monte Carlo Simulationsmentioning

confidence: 99%

Charge neutrality breakdown in confined aqueous electrolytes: Theory and simulation

Colla

Girotto

Santos

et al. 2016

The Journal of Chemical Physics

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BrazilWe study, using Density Functional theory and Monte Carlo simulations, aqueous electrolyte solutions between charged infinite planar surfaces, in a contact with a bulk salt reservoir. In agreement with recent experimental observations [Z. Luo et al., Nat. Comm. 6, 6358 (2015)], we find that the confined electrolyte lacks local charge neutrality. We show that a Density Functional Theory (DFT) based on a bulk-HNC expansion properly accounts for strong electrostatic correlations and allows us to accurately calculate the ionic density profiles between the charged surfaces, even for electrolytes containing trivalent counterions. The DFT allows us to explore the degree of local charge neutrality violation, as a function of plate separation and bulk electrolyte concentration, and to accurately calculate the interaction force between the charged surfaces.

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“…and N f is the number of overlaps of the plates with the ions after a displacement ∆R that moves the two plates farther apart (superscript f stands for farther) 80 .…”

Section: Model and Monte Carlo Simulationsmentioning

confidence: 99%

Charge neutrality breakdown in confined aqueous electrolytes: Theory and simulation

Colla

Girotto

Santos

et al. 2016

The Journal of Chemical Physics

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“…Again we will use the modified 3d Ewald summation given by Eq. (17). This means that the box will be replicated in all 3 dimensions.…”

Section: H H Hmentioning

confidence: 99%

Simulations of Coulomb systems with slab geometry using an efficient 3D Ewald summation method

Santos

Girotto

Levin

2016

The Journal of Chemical Physics

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We present a new approach to efficiently simulate electrolytes confined between infinite charged walls using a 3d Ewald summation method. The optimal performance is achieved by separating the electrostatic potential produced by the charged walls from the electrostatic potential of electrolyte. The electric field produced by the 3d periodic images of the walls is constant inside the simulation cell, with the field produced by the transverse images of the charged plates canceling out. The non-neutral confined electrolyte in an external potential can be simulated using 3d Ewald summation with a suitable renormalization of the electrostatic energy, to remove a divergence, and a correction that accounts for the conditional convergence of the resulting lattice sum. The new algorithm is at least an order of magnitude more rapid than the usual simulation methods for the slab geometry and can be further sped up by adopting a particle-particle particle-mesh approach.

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“…Second, in two closely related approaches put forward by Castañeda-Priego et al [56,57], and Colla et al [58] (see also Ref. [59]), the exact validity of the Kirkwood-Buff relation is enforced by a self-consistent combination of the PB-based renormalized jellium model for calculating Z eff and κ eff , and the Rogers-Young integral equation scheme for S(q) with adjusted mixing parameter. Which of the above noted methods of calculating Π is more accurate in comparison with benchmark PM simulations is a matter of future assessment.…”

Section: Osmotic Pressure Calculationmentioning

confidence: 99%

Ultrafiltration of charge-stabilized dispersions at low salinity

et al. 2016

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We present a comprehensive study of cross-flow ultrafiltration (UF) of charge-stabilized suspensions, under low-salinity conditions of electrostatically strongly repelling colloidal particles. The axially varying permeate flux, near-membrane concentration-polarization (CP) layer and osmotic pressure profiles are calculated using a macroscopic diffusion-advection boundary layer method, and are compared with filtration experiments on aqueous suspensions of charge-stabilized silica particles. The theoretical description based on the one-component macroion fluid model (OCM) accounts for the strong influence of surface-released counterions on the renormalized colloid charge and suspension osmotic compressibility, and for the influence of the colloidal hydrodynamic interactions and electric double layer repulsion on the concentration-dependent suspension viscosity η, and collective diffusion coefficient Dc. A strong electro-hydrodynamic enhancement of Dc and η, and likewise of the osmotic pressure, is predicted theoretically, as compared with their values for a hard-sphere suspension. We also point to the failure of generalized Stokes-Einstein relations describing reciprocal relations between Dc and η. According to our filtration model, Dc is of dominant influence, giving rise to an only weakly developed CP layer having practically no effect on the permeate flux. This prediction is quantitatively confirmed by our UF measurements of the permeate flux using an aqueous suspension of charged silica spheres as the feed system. The experimentally detected fouling for the largest considered transmembrane pressure values is shown not to be due to filter cake formation by crystallization or vitrification.

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Equation of state of charged colloidal suspensions and its dependence on the thermodynamic route

Cited by 22 publications

References 64 publications

Charge neutrality breakdown in confined aqueous electrolytes: Theory and simulation

Charge neutrality breakdown in confined aqueous electrolytes: Theory and simulation

Simulations of Coulomb systems with slab geometry using an efficient 3D Ewald summation method

Ultrafiltration of charge-stabilized dispersions at low salinity

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