Competitive separation of di- vs. mono-valent cations in electrodialysis: Effects of the boundary layer properties

Kim, Younggy; Walker, W. Shane; Lawler, Desmond F.

doi:10.1016/j.watres.2012.01.004

Cited by 77 publications

(51 citation statements)

References 31 publications

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“…This value is an order of magnitude higher than the largest previous estimates from literature for traditional ED (Moon et al, 2004;Kim et al, 2012;Choi et al, 2002). The higher value is likely due to the thicker chamber widths and slower flow rate of this system compared to traditional ED applications.…”

Section: Boundary Layer Thicknessmentioning

confidence: 56%

“…Equation 1.1 is commonly used to describe the relationship between applied current density (I) and the resulting ionic flux in electrodialytic systems (Kim, Walker & Lawler 2012;Moon et al 2004). Here, the summative flux of charges in the solution is determined to be…”

Section: Flux and Current Relationshipmentioning

confidence: 99%

“…Many, but not all, models determine empirical parameters that characterise the system for a given salt and set of operating conditions. Existing models largely focus on describing process operating conditions (Kodym et al 2012;Sadrzadeh, Kaviani & Mohammadi 2007), DBL transport effects (Kim, Walker & Lawler 2012), overlimiting current mechanisms (Nikonenko et al 2010;Zabolotskii et al 2013) or identifying membrane properties in relation to ion transport (Kraaijeveld et al 1995). Four modelling elements are required to mechanistically study system performance relating to inorganic ion transport during nutrient recovery from centrate.…”

Section: Modelling Electrodialysismentioning

confidence: 99%

“…These elements include the capacity to model a) multi-ion systems, b) pH, c) speciation (ion pairing and acid base dissociation), and d) scaling of the membranes. A summary of existing literature relating to these elements is shown below in Table 1.1 shows that the majority of existing models are focused on describing the fluxes of single salts (Lee et al, 2006;Mohammadi et al, 2005;Moon et al, 2004;Tanaka, 2013;Ortiz et al, 2005), or only have the capacity to model just few different ionic species in solution (Kraaijeveld et al, 1995;Kim et al, 2012;Nikonenko et al, 2003). Some models have taken into account the effects of pH on mass transport in the system (Zabolotskii et al, 2013;Kraaijeveld et al, 1995;Nikonenko et al, 2003Nikonenko et al, , 2010, but only Dykstra et al (2014) and Stodollick et al (2014) simulated pH through the system and how this affects mass transport and acid-base dissociation.…”

Section: Modelling Electrodialysismentioning

confidence: 99%

“…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%

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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: Boundary Layer Thicknessmentioning

confidence: 56%

Section: Flux and Current Relationshipmentioning

confidence: 99%

Section: Modelling Electrodialysismentioning

confidence: 99%

Section: Modelling Electrodialysismentioning

confidence: 99%

Section: Governing Equationmentioning

confidence: 99%

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Nutrient recovery from wastewater using electrodialysis

Brewster¹

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Water Desalination: Electrostatic and Electrochemical Separation Processes

Shanbhag

Karimi

Whitacre

et al. 2019

Encyclopedia of Water

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Electrostatic and electrochemical separations offer significant potential in the deionization of water as either stand‐alone processes or pre‐/posttreatment processes for achieving targeted water quality. This article critically reviews these electrically driven methods for the desalination of water. We begin by chronicling the historical development of electrostatic and electrochemical separation processes in both research and commercial applications. Further, we review the fundamental transport and reaction phenomenon critical to process performance and define metrics for assessing this performance. The subsequent two sections provide a deeper review of CDI (electrostatic) and electrosorption (electrochemical ion removal), and electromembrane separation systems, such as electrodialysis (ED), electrodialysis reversal (EDR), and electrodeionization (EDI), as well as membrane‐assisted electrosorption systems. For each of these electrostatic or electrochemical separation methods, we discuss the process fundamentals, key challenges associated with these technologies as well as recent innovations in materials and process design that are overcoming historical limits. Finally, we conclude with a discussion of practical applications of these methods and summarize opportunities to advance electrochemical processes for materially and energy‐efficient ionic separations.

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Technologies to Remove Selenium from Water and Wastewater

Lichtfouse

Morin‐Crini

Bradu

et al. 2021

Environmental Chemistry for a Sustainable World

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After major pollution by nitrates and pesticides, soils and groundwater in some parts of the world are now facing the emergence of a third major issue of selenium (Se) contamination. Selenium occurrence in ecosystems results naturally from weathering of Se-containing rocks, and is further aggravated by human activities. Selenium is ubiquitous in the environment, and the two main sources of human exposure by Se are food and water. Se, a metalloid, is an important micronutrient due to Se antioxidant, anti-inflammatory and chemo-preventative properties. At normal dietary doses, selenium is an essential diet element that has nutritional proper-E. Lichtfouse (*)

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Competitive separation of di- vs. mono-valent cations in electrodialysis: Effects of the boundary layer properties

Cited by 77 publications

References 31 publications

Nutrient recovery from wastewater using electrodialysis

Nutrient recovery from wastewater using electrodialysis

Water Desalination: Electrostatic and Electrochemical Separation Processes

Technologies to Remove Selenium from Water and Wastewater

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