A comparison of multicomponent electrosorption in capacitive deionization and membrane capacitive deionization

Hassanvand, Armineh; Chen, George Q.; Webley, Paul A.; Kentish, Sandra E.

doi:10.1016/j.watres.2017.12.015

Cited by 151 publications

(71 citation statements)

References 45 publications

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“…No selectivity was found for STP effluent ( ̅ = 0.97; SD = 0.16; N = 4) while S could not be calculated for Eumes river water due to the lack of hardness ions. Preferential removal of bivalent ions is common in MCDI; it is observed in both synthetic feed mixtures [19,32] and real feed water [9]. This phenomenon is the result of diffusion kinetics and adsorption equilibria in MCDI and is attributed to the preferential storage of multivalent ions in ion exchange membranes [32,33].…”

Section: Cost Estimatementioning

confidence: 99%

Membrane Capacitive Deionization for Cooling Water Intake Reduction in Thermal Power Plants: Lab to Pilot Scale Evaluation

et al. 2020

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Cooling of thermal power stations requires large amounts of surface water and contributes to the increasing pressure on water resources. Water use efficiency of recirculating cooling towers (CT) is often kept low to prevent scaling. Partial desalination of CT feed water with membrane capacitive deionization (MDCI) can improve water quality but also results in additional water loss. A response surface methodology is presented in which optimal process conditions of the MCDI-CT system are determined in view of water use efficiency and cost. Maximal water use efficiency at minimal cost is found for high adsorption current (2.5 A) and short adsorption time (900 s). Estimated cost for MCDI to realize maximal MCDI-CT water use efficiency is relatively high (2.0–3.1 € m−3evap), which limits applicability to plants facing high intake water costs or water uptake limitations. MCDI-CT pilot tests show that water use efficiency strongly depends on CT operational pH. To allow comparison among pilot test runs, simulation software is used to recalculate CaCO3 scaling and acid dosage for equal operational pH. Comparison at equal pH shows that MCDI technology allows a clear reduction of CT water consumption (74%–80%) and acid dosage (63%–80%) at pH 8.5.

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Section: Cost Estimatementioning

confidence: 99%

Membrane Capacitive Deionization for Cooling Water Intake Reduction in Thermal Power Plants: Lab to Pilot Scale Evaluation

et al. 2020

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“…As CDI gets more and more attention, many studies have been carried out by scholars all around the world. Most researches are about the electrode materials (carbon aerogel, carbon nanotubes, grapheme) [4][5][6][7], integration of microbial fuel cells and CDI [8,9], membrane CDI [10,11] and flow-electrode CDI [12,13].…”

Section: Introductionmentioning

confidence: 99%

Capacitive deionization using a pulsed power supply for water treatment

Jin¹,

Hu²,

Sun³

et al. 2019

Desalination and Water Treatment

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A capacitive deionization system utilizing a pulsed power supply was designed and investigated for desalination. In most studies on capacitive deionization, direct current power supply is the most common power source. Compared with traditional direct-current capacitive deionization, pulsed-capacitive deionization exhibits some excellent properties in desalination: lower power consumption, higher removal rate. The optimal operational conditions of a pulsed power supply in capacitive deionization were discussed in this study. From the experiment results, as for NO 3 of initial concentration 40 mg/L, a duty cycle of 50% and a frequency of 1000 Hz were optimal. From the theory of electrolyte solution, the optimal frequency is related to properties of ion, such as: ionic radius, valence, ion mobility, and also related to the concentration of ion. The results of molecular dynamics simulation were consistent with the experimental results. the reasons for excellent performances of pulsed-capacitive deionization in desalination may be that: the effect of concentration polarization and the migration resistance from solution to the EDL were reduced. Pulsed-capacitive deionization could be used for low concentration water desalination and it provides a new idea for the preparation of ultra pure water and the advanced treatment of wastewater.

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“…CDI and CAPMIX technologies are EDLC-based technology. Both technologies have been widely investigated in the field of water technology in the past years, and several EDLC cell architectures have been proposed for both systems, e.g., flow-by CDI [69][70][71][72][73] , Membrane CDI 72,74,75 , flow-through electrode 76 , flow-electrode CDI 77,78 , and wire-shaped electrode 19,22,79 . Conventionally, a flow-by CDI is considered as the "conventional" design for CDI application, while the Membrane CDI is the conventional design for CAPMIX application.…”

Section: Principles Of Capacitive Deionization (Cdi) and Capacitive Mmentioning

confidence: 99%

“…However, besides the electrode behavior, the IEMs could also influence Λ | . For instance, the IEMs show a selectivity towards specific ions based on their valence 71,75 or size 71 . The individual effect of the electrodes and the IEMs is challenging to distinguish in CO2-MCDI experiments.…”

Section: Absorption Efficiency In Co2-mcdimentioning

confidence: 99%

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Capacitive processes for carbon capture and energy recovery from CO2 emissions : Shaping a new technology going from water to gas applications

Legrand¹

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Nonetheless, how can we convert a water technology into a gas technology? The first step is to identify a strategy to produce ions from CO2 gas. As CO2 gas is not an ion, the CDI and CAPMIX cells are not directly usable with gas streams. Nevertheless, ions can be generated from CO2 by sparging CO2 gas in water, a process in which bicarbonate ions are formed (see Box 1). 1.3.2. Electrochemical pH swing CO2 capture can be achieved by generating a pH swing between two chambers in an electrochemical cell. The electrochemical pH swing has been mostly investigated in electrodialysis cell 62,63 and bipolar electrodialysis cell 49,53-55. The CO2 absorption takes place in the alkaline compartment (high pH) through the reaction of CO2 with hydroxide (CO + OH → HCO), whereas the CO2 desorption takes place in the acidic compartment (HCO + H → CO). Fig. 1.6 shows an example of CO2 capture with bipolar electrodialysis. Supercapacitive swing adsorption (SAA) is an electrical double-layer capacitor (EDLC) for CO2 capture 58-61. The concept consists of adsorbing CO2 on the cathode in a gas channel while charging the EDLC cell in a highly concentrated NaCl solution. Fig. 1.8 shows an illustration of the SAA concept. Three mechanisms have been suggested for the CO2 gas adsorption in the electrodes, i.e. (a) adsorption of gas molecules at gas-solid interface, (b) adsorption of gas molecules at the gas-liquid interface, and (c) adsorption of ionized gas molecule 61. Adsorption at the gas-solid interface would occur when CO2 gas is adsorbed in non-filled electrode pores stimulated by a change of affinity between the pore wall and CO2 during the charging step of the cell. Adsorption at the gas-liquid interface would occur due to an increased CO2 solubility in the electrical double layer (EDL) by charging the capacitive cell. Finally, ionization adsorption occurs through the adsorption where ϵ. is the dielectric constant, ϵ 0 is the permittivity of free space, R the gas constant, T the temperature, F the Faraday constant and c 4 the ion concentration in the bulk solution. Finally, the Stern layer represents the layer of solution separating the diffuse layer, and the carbon matrix surface. In theory, ions are surrounded by a hydration shell, and therefore, the charged ions are not infinitely close to the electrode surface. IEMs are ionomer, i.e., charged polymer, which primarily act as selective charge barriers. Ideally, only anions can be transported through the AEM, and only cations can be transported through the CEM (counter-ion transport). IEMs are mainly used in CDI to improve the charge efficiency (in Membrane CDI or MCDI) 70,72 and are required in CAPMIX to generate an electrical potential.

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A comparison of multicomponent electrosorption in capacitive deionization and membrane capacitive deionization

Cited by 151 publications

References 45 publications

Membrane Capacitive Deionization for Cooling Water Intake Reduction in Thermal Power Plants: Lab to Pilot Scale Evaluation

Membrane Capacitive Deionization for Cooling Water Intake Reduction in Thermal Power Plants: Lab to Pilot Scale Evaluation

Capacitive deionization using a pulsed power supply for water treatment

Capacitive processes for carbon capture and energy recovery from CO2 emissions : Shaping a new technology going from water to gas applications

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