Comparing energy demands and longevities of membrane-based capacitive deionization architectures

Pothanamkandathil, Vineeth; Gorski, Christopher A.

doi:10.1039/d2ew00188h

Cited by 6 publications

(11 citation statements)

References 72 publications

(120 reference statements)

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“…Although soluble redox mediators included in electrode rinse have recently been shown to further reduce energy consumption relative to electrosorption approaches, 17,18 their crossover through the membrane raises environmental and stability concerns. Thus, the use of electrode rinse in a multichannel system offers a compelling strategy to increase the charge-storage capacity of electrodes, thereby improving desalination performance in an environmentally benign manner at a low cell voltage.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The recirculated electrode rinse also allows the amount of Na + in the electrode rinse to remain unchanged because Na + separated from the diluate returns back to the concentrate, which is advantageous over some of the previous systems involving an additional step to release the accumulated ions. 19,4,48,17,49,50 An effluent concentration of approximately 44.8 mM was produced at a current density of 0.55 mA cm −2 (Figure 3a), which yielded a charge efficiency of ≈0.96. The use of higher current densities allowed for separating salt to a greater extent, thus, producing a lower effluent concentration (Figure S7).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Unlike ED, which is driven by water electrolysis with a theoretical minimum voltage of 1.23 V (typically >2 V due to overpotentials), electrosorption and intercalation electrodes provide the driving force for salt separation through ion exchange membranes at relatively low voltages (<1.2 V). Although soluble redox mediators included in electrode rinse have recently been shown to further reduce energy consumption relative to electrosorption approaches, , their crossover through the membrane raises environmental and stability concerns. Thus, the use of electrode rinse in a multichannel system offers a compelling strategy to increase the charge-storage capacity of electrodes, thereby improving desalination performance in an environmentally benign manner at a low cell voltage.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Desalination Performance Using Phosphate Buffer-Mediated Redox Reactions of Manganese Oxide Electrodes in a Multichannel System

Akinyemi,

Chen,

Kim

2023

ACS Appl. Mater. Interfaces

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Water desalination mediated by electrochemical reactions to directly capture and release salt at electrode materials offers a low-voltage method for producing freshwater. Developing new system designs has allowed electrode materials to maximize their capacity for salt separation, especially when a multichannel system is used to introduce a separate electrode rinse solution. Here, we show that the use of an additive can provide a new strategy for improving electrode capacity and, hence desalination performance, which so far has been limited to increasing the electrolyte concentration. A custom-built, 2/2-channel flow cell divided by two cation exchange membranes and an anion exchange membrane was fed with 50 mM NaCl as the feed (two inner channels) and 0.5 M NaCl containing up to 0.1 M phosphate as the electrode rinse (two outer channels). Using manganese oxide electrodes with phosphate buffer-mediated redox reactions exhibited an improved desalination capacity of 68.0 ± 5.2 mg g −1 (0.55 mA cm −2 ) and a rate of 5.6 ± 1.3 mg g −1 min −1 (0.96 mA cm −2 ). The improvement was attributed to the buffer that served as a proton donor for promoting the H + insertion reaction of amorphous or poorly crystalline MnO 2 . Additionally, the buffering capacity against acidification and the creation of insoluble manganese phosphate on the electrode surface prevented the dissolution of Mn 2+ , which could otherwise occur at the anode due to a decrease in the local pH upon H + deinsertion. Thus, the use of manganese oxide electrodes coupled with phosphate provides a new strategy of increasing electrode capacity for water desalination.

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced Desalination Performance Using Phosphate Buffer-Mediated Redox Reactions of Manganese Oxide Electrodes in a Multichannel System

Akinyemi,

Chen,

Kim

2023

ACS Appl. Mater. Interfaces

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“…It is also commonly considered an environmentally friendly, economical, and easyoperating technique. [20][21][22][23] CDI executes the electrosorption to remove the ions by ingesting them into a pair of charged porous carbon…”

Section: Introductionmentioning

confidence: 99%

“…It is also commonly considered an environmentally friendly, economical, and easy‐operating technique. [ 20–23 ]…”

Section: Introductionmentioning

confidence: 99%

Binder‐Free Wood Converted Carbon for Enhanced Water Desalination Performance

Neupane

Zia

et al. 2022

Adv Funct Materials

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The design and synthesis of high‐performance and economical carbon electrodes play a critical role in developing energy‐efficient water desalination technologies. As a sustainable approach, low‐cost and abundant biomass materials are promising candidates to prepare porous carbon for capacitive deionization. In this study, binder‐free porous carbon sheets are successfully prepared using natural balsa, pine, and basswood by thermal carbonization and treated by chemical activation. The carbon electrode materials converted from balsa and pine exhibit a comparable salt adsorption performance by capacitive deionization due to the extensive surface area, substantial electrical property, and superior hydrophilic performance. The following activation treatment of the balsa‐converted carbon further enhances the surface and electrical properties and benefits the desalination performance. The salt adsorption capacity of the activated balsa electrode exhibits 12.45 mg g−1. Additionally, 19.52 mg g−1 Pb2+ and 20.06 mg g−1 Cr3+ heavy metal adsorption capacity is also observed with the activated balsa electrode in 100 mg L−1 PbCl2 and 50 mg L−1 CrCl3, respectively. To the best of authors’ knowledge, this is the highest NaCl adsorption capacity performance reported thus far by using pure wood converted carbon as the electrode, and these promising results indicate that activated balsa is an extraordinary material for water desalination.

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Reducing Ohmic Resistances in Membrane Capacitive Deionization Using Micropatterned Ion‐Exchange Membranes, Ionomer Infiltrated Electrodes, and Ionomer‐Coated Nylon Meshes

Hasan,

Shrimant,

Waters

et al. 2024

Small Structures

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Membrane capacitive deionization (MCDI) is an emerging water desalination platform that is compact, electrified, and does not require high‐pressure piping. Herein, highly conductive poly(phenylene alkylene) ion‐exchange membranes (IEMs) are micropatterned with different surface geometries for MCDI. The micropatterned membranes increase the interfacial area with the liquid stream leading to a 700 mV reduction in cell voltage when operating at constant current (2 mA cm−2; 2000 ppm NaCl feed) while improving the energy normalized adsorbed salt (ENAS) value by 1.4 times. Combining the micropatterned poly(phenylene alkylene) IEMs with poly(phenylene alkylene) ionomer‐filled electrodes reduces the cell voltage by 1000 mV and improves the ENAS values by 2.3 times relative to the base case. This reduction in cell voltage allows for higher current density operation (i.e., 3–4 mA cm−2) . The reduction in cell voltage is ascribed to the ameliorating ohmic resistances related to ion transport at the membrane‐process stream interface and in the carbon cloth electrode. Finally, porous ionic conductors are implemented into the spacer channel with flat and micropatterned IEM configurations and ionomer infiltrated electrodes. For the configuration with flat IEMs, the porous ionic conductor improves ENAS values across the current density regime (2–4 mA cm−2), while for micropatterned IEMs it gets improved only at 4 mA cm−2.

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Comparing energy demands and longevities of membrane-based capacitive deionization architectures

Abstract: Several capacitive deionization (CDI) cell architectures employ ion-exchange membranes to control the chemistry of the electrolyte contacting the electrodes. Here, we experimentally examined how exposing carbon electrodes to either a...

Cited by 6 publications

References 72 publications

Enhanced Desalination Performance Using Phosphate Buffer-Mediated Redox Reactions of Manganese Oxide Electrodes in a Multichannel System

Enhanced Desalination Performance Using Phosphate Buffer-Mediated Redox Reactions of Manganese Oxide Electrodes in a Multichannel System

Binder‐Free Wood Converted Carbon for Enhanced Water Desalination Performance

Reducing Ohmic Resistances in Membrane Capacitive Deionization Using Micropatterned Ion‐Exchange Membranes, Ionomer Infiltrated Electrodes, and Ionomer‐Coated Nylon Meshes

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