Efficient and stable operation of capacitive deionization assessed by electrode and membrane asymmetry

Barcelos, Kamilla M.; Oliveira, Kaíque S.G.C.; Silva, Domingos S. A.; Urquieta‐González, Ernesto A.; Ruotolo, Luís A.M.

doi:10.1016/j.electacta.2021.138631

Cited by 12 publications

(4 citation statements)

References 52 publications

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“…The long-term stability of electrodes is always the most important parameter to achieve the scalable application of CDI. − First, the same carbon electrodes were used for eliminating the difference of substrate carbon and other possible factors. Obviously, the conductivity outline of each cycle for C-MCDI maintained better than that for CDI and the decreased degree of conductivity was also higher for C-MCDI (Figures S7a,b).…”

Section: Resultsmentioning

confidence: 99%

Poly(arylene alkylene)-Based Ion-Exchange Polymers for Enhancing Capacitive Desalination Capacity and Electrode Stability

Xu,

Jiang,

Zhang

et al. 2023

Ind. Eng. Chem. Res.

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Section: Resultsmentioning

confidence: 99%

Poly(arylene alkylene)-Based Ion-Exchange Polymers for Enhancing Capacitive Desalination Capacity and Electrode Stability

Xu,

Jiang,

Zhang

et al. 2023

Ind. Eng. Chem. Res.

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“…These methods produce clean water but are either expensive or inefficient in terms of energy consumption. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Capacitive deionization (CDI) is considered an emerging technique for the removal of ions from aqueous solutions that can be effectively used in water desalination and water treatment processes. In CDI, the electrochemical cell consists of the electrodes, the current collectors, and the nonconductive spacer.…”

Section: Introductionmentioning

confidence: 99%

“…[1,20] Another problem with carbon-based electrodes is that they can be degraded by parasitic reactions (e.g., anode oxidation) at excessively high voltages, which reduce the efficiency of the process in longterm operation. In particular, highly positive anode potentials [8,9] and the presence of dissolved oxygen (DO) in the feed water promotes the formation of strong reactive oxygen species that can react with the carbon in the anode. [10][11][12][13] Corrosion, in turn, negatively affects the anode potential and increases the contact resistance.…”

Section: Introductionmentioning

confidence: 99%

Development of Composite Nanostructured Electrodes for Water Desalination via Membrane Capacitive Deionization

Bakola,

Kotrotsiou,

Ntziouni

et al. 2024

Macromol. Rapid Commun.

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Novel two‐layer nanostructured electrodes were successfully prepared for their application in membrane capacitive deionization (MCDI) processes. Nanostructured carbonaceous materials such as graphene oxide (GO) and carbon nanotubes (CNTs), as well as activated carbon (AC) were dispersed in a solution of poly(vinyl alcohol) (PVA), mixed with polyacrylic acid (PAA) or polydimethyldiallylammonium chloride (PDMDAAC), and subsequently cast on the top surface of an activated carbon‐based modified graphite electrode to form a thin composite layer that was cross‐linked with glutaraldehyde (GA). Cyclic Voltammetry (CV) was performed to investigate the electrochemical properties of the composite electrodes and desalination experiments were conducted in batch mode using a MCDI unit cell to investigate the effects of i) the nanostructured carbonaceous material, ii) its concentration in the polymer blend, and iii) the molecular weight of the polymers on the desalination efficiency of the system. Comparative studies with commercial membranes were performed proving that the composite nanostructured electrodes were more efficient in salt removal. The improved performance of the composite electrodes was attributed to the ion exchange properties of the selected polymers and the increased specific capacitance of the nanostructured carbonaceous materials. This research paves the way for wider application of MCDI in water desalination.This article is protected by copyright. All rights reserved

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“…This decrease is primarily due to the corrosion of carbon in the anode . Corrosion is driven by highly positive anode potentials , and the presence of dissolved oxygen (DO) in the feedwater. − As shown in eq , carbon oxidation can lead to loss of carbon and generation of H + that decrease the bulk pH. …”

Section: Introductionmentioning

confidence: 99%

Improving Long-Term Anode Stability in Capacitive Deionization Using Asymmetric Electrode Mass Ratios

Algurainy

Call

2021

ACS EST Eng.

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Activated carbon (AC) electrodes are used for desalination in capacitive deionization (CDI) because they provide a large, porous surface area at a low cost. In short-term tests, AC electrodes can achieve relatively high salt adsorption capacities. In long-term tests, desalination performance degrades significantly. The poor performance has been attributed to the corrosion of carbon in the anode electrode. Here, we show a simple strategy to improve anode stability by changing the mass ratio of AC electrodes (asymmetric configuration) in flow-through CDI (FT-CDI). Increasing the anode mass by double and triple decreased the anode half-cell potential by up to 21 and 64%, respectively, relative to cells with single anodes. Less positive anode potentials were associated with smaller shifts in the anode potential of zero charge and lower acidity in the effluent. Additional evidence for improved anode stability in the asymmetric configurations was the significantly lower charge transfer resistance and oxygen to carbon ratio content of the anodes at the end of the tests. After 48 h of operation, the salt adsorption capacity decreased by 68% in symmetric cells, but, in asymmetric cells, it was more stable and decreased by only 47% (double anode) and 17% (triple anode). These trends were consistent when the anode was located upstream or downstream of the cathode. We attribute the improved anode stability to reduced oxidation in the asymmetric cells, which was driven by lower oxidative half-cell potentials. This, in turn, maintained a stable desalination performance over long-term operation. Our results demonstrate that increasing the anode mass is an effective strategy to extend anode stability and improve long-term salt removal in FT-CDI.

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Efficient and stable operation of capacitive deionization assessed by electrode and membrane asymmetry

Cited by 12 publications

References 52 publications

Poly(arylene alkylene)-Based Ion-Exchange Polymers for Enhancing Capacitive Desalination Capacity and Electrode Stability

Poly(arylene alkylene)-Based Ion-Exchange Polymers for Enhancing Capacitive Desalination Capacity and Electrode Stability

Development of Composite Nanostructured Electrodes for Water Desalination via Membrane Capacitive Deionization

Improving Long-Term Anode Stability in Capacitive Deionization Using Asymmetric Electrode Mass Ratios

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