Increasing RO efficiency by chemical-free ion-exchange and Donnan dialysis: Principles and practical implications

Vanoppen, Marjolein; Stoffels, Griet; Demuytere, Célestin; Bleyaert, Wouter; Verliefde, Arne

doi:10.1016/j.watres.2015.04.030

Cited by 41 publications

(26 citation statements)

References 22 publications

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“…Vanoppen et al [164] calculated the influence of pretreatment to reduce the cost of brine discharge. By introducing ion-exchange as pre-treatment, brine discharge cost was reduced because of increasing recovery rate, thus the total cost was reduced from 1.9 to 1.6 €/m 3 .…”

Section: Ro Element Performance and Other Cost Driversmentioning

confidence: 99%

How RO membrane permeability and other performance factors affect process cost and energy use: A review

2019

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Reverse osmosis (RO) technology has progressed steadily over the last few decades. Those gains were achieved through improvements in both RO membrane element performance and energy recovery technologies. However, some recent literature indicates that RO membrane water permeability is approaching performance limits imposed by transport processes and thermodynamic constraints. This paper reviews how RO membrane element performance affects the cost of RO processes, especially the specific energy consumption. RO membrane performance encompasses water permeability, salt permeability, and other some characteristics of the RO element. This paper considers not only conventional RO processes, but also the recently proposed closed-circuit RO and batch RO processes. Even if the membrane water permeability increases, little additional effect is found when the membrane water permeability exceeds around 3 LMH/bar for seawater RO and 8 LMH/bar for brackish water RO in conventional single-stage RO. Increasing membrane water permeability has the potential to decrease membrane surface area and associated costs. A major limitation of most existing literature is that performance is evaluation on in terms of the initial operating conditions. Chronological changes, such as result from fouling, must also be considered to accurately validate how membrane element performance affects RO cost.

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Section: Ro Element Performance and Other Cost Driversmentioning

confidence: 99%

How RO membrane permeability and other performance factors affect process cost and energy use: A review

2019

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“…The fundamental principle of Fredrick G. Donnan's 1924 study established the Donnan equilibrium from the electrostatic repulsion of co-ions from the phases [14]. Electrolytic solutions are at equilibrium when the electrochemical potential difference across the membrane equates to the Donnan potential of the membrane [15]. Theoretically, IED or the DD process is not prone to fouling [16] and has a low energy consumption.…”

Section: Introductionmentioning

confidence: 99%

Ion Exchange Dialysis for Aluminium Transport through a Face-Centred Central Composite Design Approach

et al. 2020

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An ion exchange dialysis (IED) is used in the recovery of aluminium from residue. In this paper, the face-centred central composite design (FC-CCD) of the response surface methodology (RSM) and desirability approach is used for experimental design, modelling and process optimization of a counter flow IED system. The feed concentration, feed flowrate, sweep flowrate and sweep concentration were selected as the process variables, with the Al transport across a Nafion 117 membrane as the target response. A total of 30 experimental runs were conducted with six centre points. The response obtained was analysed by analysis of variance (ANOVA) and fitted to a second-order polynomial model using multiple regression analysis. The actual R2 and standard deviation of the model are 0.9548 and 0.2932, respectively. Depending on the time zone of reference (24 h or 32 h), the highest enrichment of >1.50 was achieved. The designed variables were numerically optimized by applying the desirability function to achieve the maximum Al transport. The optimised condition values were found to be a feed concentration of 1600 ppm, feed flowrate of 61.76%, sweep flowrate of 37.50% and sweep concentration of 0.75 N for the 80% target response at 32 h. Overall, the model can be used to effectively predict Al recovery using the designed system.

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“…G Donnan's 1924 study establishesd the donnan equilibrium from the electrostatic repulsion of co-ions from the phases [13]. Electrolytic solutions are at equilibrium when the electrochemical potential difference across the membrane equates to the donnan potential of the membrane [14]. The IED or DD process is not prone to fouling and has a low energy consumption.…”

Section: Introductionmentioning

confidence: 99%

Ion Exchange Dialysis for Aluminium Transport through a Face Centered Central Composite Design Approach

Asante-Sackey¹,

Rathilal²,

Pillay³

et al. 2019

Preprint

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An ion exchange dialysis (IED) is used in the recovery of aluminium from residue. In this papers, the face-centered central composite design (FC-CCD) of the response surface methodology (RSM) and desirability approach is used for experimental design, modelling and process optimization of a counter flow IED system. The feed concentration, feed flowrate, sweep flowrate and sweep concentration are selected as the process variables, with the Al-transport across a Nafion 117 membrane as the target response. A total of 30 experimental runs were conducted with 6 center points. The response obtained was analysed by analysis of variance (ANOVA) and fitted to a second-order polynomial model using multiple regression analysis. The actual R 2 and standard deviation of the model are 0.9548 and 0.2932 respectively. The influences of significant variables are plotted on 3D surface and contour plots. The designed variables were numerically optimized by applying the desirability function to achieve the maximum Al-transport. The optimised condition values were found to be feed concentration (1600 ppm), feed flowrate (61.76%), sweep flowrate (37.50%) and sweep concentration (0.75 N) for the 80% target response at 32hrs. Overall, the model can be used to effectively predict Al-recovery using the designed system.

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Increasing RO efficiency by chemical-free ion-exchange and Donnan dialysis: Principles and practical implications

Cited by 41 publications

References 22 publications

How RO membrane permeability and other performance factors affect process cost and energy use: A review

How RO membrane permeability and other performance factors affect process cost and energy use: A review

Ion Exchange Dialysis for Aluminium Transport through a Face-Centred Central Composite Design Approach

Ion Exchange Dialysis for Aluminium Transport through a Face Centered Central Composite Design Approach

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