Intensification of demineralization process and decrease in scaling by application of pulsed electric field with short pulse/pause conditions

Mikhaylin, Sergey; Nikonenko, Victor; Pourcelly, G.; Bazinet, Laurent

doi:10.1016/j.memsci.2014.05.045

Cited by 68 publications

(94 citation statements)

References 28 publications

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“…The Nernst-Planck equation is used to account for ionic flux in the direction perpendicular to the membranes (the x-direction). It is assumed that no convection occurs in the x-direction (Moon et al, 2004;Kim et al, 2012;Nikonenko et al, 2014). Under this assumption, the assumption that migration and diffusion only occur in the x-direction, the resulting governing equation for concentration is shown in Equation 2.1.…”

Section: Governing Equationmentioning

confidence: 99%

“…A common method of doing this is to use an estimated transport number for each ion to describe the proportion of current transported through the membrane by that specific ion (Nikonenko et al, 2014). However, an alternative approach is proposed here.…”

Section: Membrane Transportmentioning

confidence: 99%

“…The diffusion coefficient of ions passing through the membrane is 0.1-0.001 times that of in solution (Nikonenko et al, 2014). Therefore, to account for the additional resistance imposed by the membrane, the diffusion coefficients of counter-ions are multiplied by 0.1 and that of co-ions are multiplied by 0.01.…”

Section: Diffusion Coefficientsmentioning

confidence: 99%

“…It is formed from the potential gradient used in the Nernst-Planck equation as well as the Donnan exclusion potential (also known as the junction potential, E Donnan ). Rearranged, the Nernst-Planck equation combined with the assumption of electroneutrality results in the equation for potential gradient (Moon et al, 2004), which is also related to the electric field strength (E) (Nikonenko et al, 2014) …”

Section: Total and Electrode Potential Lossesmentioning

confidence: 99%

“…To model the system with no unknown parameters the DBL thickness could be estimated using the Leveque equation (Newman 1991, Nikonenko et al 2014. A benefit of including parameter estimation is that, as shown in Figure 2.2, the method highlights the sharp increase in the objective function for DBL thicknesses below approximately 0.5 mm, indicating that overestimating the DBL thickness may be less erroneous than underestimation.…”

Section: Boundary Layer Thicknessmentioning

confidence: 99%

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Nutrient recovery from wastewater using electrodialysis

Brewster¹

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The production of synthetic fertilisers from traditional sources has several issues regarding sustainability, particularly the energy intensity required for production, limited mineral resources and loss of terrestrial environment. Nutrient recovery from wastewaters is an opportunity for alternative fertiliser manufacture, largely due to the high quantities of nutrients present. Electrodialysis (ED) is an optimal technology to recover, particularly, NH 4 + -N and K + -K. In this thesis, a mechanistic modelling approach is used to study ED for nutrient recovery. Existing ED models lack the capacity to mechanistically evaluate complex, multi-ion solutions (like real wastewater), the integration of electrochemistry and physicochemical phenomena across the whole reactor domain, and model validation using system dynamics. These limitations are addressed by development of a mechanistic modelling approach, with key mechanisms determined through targeted laboratory scale experiments using synthetic and real wastewaters. The first major study in this thesis includes development of a mechanistic model validated using dynamic experiments fed with synthetic wastewater. It was found that membrane resistance was the major contributor to potential drop and that apparent boundary layers were relatively thick (3 ± 1 mm) due to reactor design and operational conditions. This study also established that non-ideal solution effects such as ion pairing and ionic activity had a major impact, enhancing the capability of ED to recover monovalent nutrient ions such as K + and NH 4 + . The second major study used real centrifuged anaerobic digester rejection water (centrate) to study membrane scaling. Dynamic laboratory experiments demonstrated electro-concentration of nutrients in centrate to several times the feed concentration. An 87±7% by weight reduction in scale occurred when the centrate was pre-treated by upstream struvite recovery and the product pH was controlled at pH 5, compared to untreated centrate and no pH control. A mechanistic model for the inorganic processes was developed by extending the previously developed model to include the composition of a real wastewater feed solution and precipitation. This extended model revealed a reduction in struvite scale to the removal of phosphate during the struvite pretreatment, and reduction in calcium carbonate scale to pH control resulting in the stripping of carbonate as carbon dioxide gas; indicating that multiple strategies may be required to control precipitation. A third major study evaluated the mechanisms limiting high product concentrations during electro-concentration of synthetic urine. Modelling this system using similar methods to the first study identified that high concentrations in the product are prevented by back diffusion of ions across the membrane, current leakage (when buffering ii capacity is exhausted), and water fluxes across the membranes. Mechanistic discoveries in this thesis provide practical guidelines for pilot and full-scale operation of nutri...

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Section: Governing Equationmentioning

confidence: 99%

Section: Membrane Transportmentioning

confidence: 99%

Section: Diffusion Coefficientsmentioning

confidence: 99%

Section: Total and Electrode Potential Lossesmentioning

confidence: 99%

Section: Boundary Layer Thicknessmentioning

confidence: 99%

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Nutrient recovery from wastewater using electrodialysis

Brewster¹

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A Review on Ion-exchange Membranes Fouling and Antifouling During Electrodialysis Used in Food Industry: Cleanings and Strategies of Prevention

2020

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During the last decades, the interest of using ion-exchange membranes (IEMs) in electrodialysis (ED) technologies has emerged in wastewater treatment, drinking water and process water production as well as food industry and more recently in processes of energy conversion and storage. Like in all membrane technologies, the problem of fouling is one of the limitative phenomena of IEM efficiency and lifetime. It mainly leads to an increase in electrical resistance of ED stacks and consequently to increase operating and membrane replacement costs, which directly affects the cost of the final product. In food industry, the composition of the treated solutions and beverages is most often complex and rich in several organic and inorganic compounds which further increases the risks and effects of fouling. Hence, a better knowledge and understanding of IEM fouling phenomena is not only the key to solve the problems and find adequate solutions, but also is one of the main factors driving membrane technology forward. This review is mainly focused on the organic fouling phenomena of IEMs during ED processes in both food and water treatment industries. It principally presents the main cleaning techniques used in industry or experimented at laboratory scale and the recent strategies of fouling prevention.

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Electrodialysis in Food Processing

Mikhaylin¹,

Bazinet²

2016

Reference Module in Food Science

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Intensification of demineralization process and decrease in scaling by application of pulsed electric field with short pulse/pause conditions

Cited by 68 publications

References 28 publications

Nutrient recovery from wastewater using electrodialysis

Nutrient recovery from wastewater using electrodialysis

A Review on Ion-exchange Membranes Fouling and Antifouling During Electrodialysis Used in Food Industry: Cleanings and Strategies of Prevention

Electrodialysis in Food Processing

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