An investigation of the impact of fouling agents in capacitive and membrane capacitive deionisation

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

doi:10.1016/j.desal.2019.01.031

Cited by 45 publications

(21 citation statements)

References 38 publications

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“…Fouling in CDI mainly occurs on electrodes and results in a reduction in electrode conductivity, electro-sorption capacitance, and cell stability. Organic foulants reduce cell performance by blocking electrode pores, competing with ions for adsorption sites, hindering ion diffusion to the electrodes, and accelerating intercalation electrode dissolution [ 445 , 446 ]. The observed scaling issues are less severe than fouling in (M)CDI studies, which may be a result of the relatively low hardness of brackish water used in (M)CDI.…”

Section: Membrane Capacitive Deionizationmentioning

confidence: 99%

Frontiers of Membrane Desalination Processes for Brackish Water Treatment: A Review

et al. 2021

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Climate change, population growth, and increased industrial activities are exacerbating freshwater scarcity and leading to increased interest in desalination of saline water. Brackish water is an attractive alternative to freshwater due to its low salinity and widespread availability in many water-scarce areas. However, partial or total desalination of brackish water is essential to reach the water quality requirements for a variety of applications. Selection of appropriate technology requires knowledge and understanding of the operational principles, capabilities, and limitations of the available desalination processes. Proper combination of feedwater technology improves the energy efficiency of desalination. In this article, we focus on pressure-driven and electro-driven membrane desalination processes. We review the principles, as well as challenges and recent improvements for reverse osmosis (RO), nanofiltration (NF), electrodialysis (ED), and membrane capacitive deionization (MCDI). RO is the dominant membrane process for large-scale desalination of brackish water with higher salinity, while ED and MCDI are energy-efficient for lower salinity ranges. Selective removal of multivalent components makes NF an excellent option for water softening. Brackish water desalination with membrane processes faces a series of challenges. Membrane fouling and scaling are the common issues associated with these processes, resulting in a reduction in their water recovery and energy efficiency. To overcome such adverse effects, many efforts have been dedicated toward development of pre-treatment steps, surface modification of membranes, use of anti-scalant, and modification of operational conditions. However, the effectiveness of these approaches depends on the fouling propensity of the feed water. In addition to the fouling and scaling, each process may face other challenges depending on their state of development and maturity. This review provides recent advances in the material, architecture, and operation of these processes that can assist in the selection and design of technologies for particular applications. The active research directions to improve the performance of these processes are also identified. The review shows that technologies that are tunable and particularly efficient for partial desalination such as ED and MCDI are increasingly competitive with traditional RO processes. Development of cost-effective ion exchange membranes with high chemical and mechanical stability can further improve the economy of desalination with electro-membrane processes and advance their future applications.

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Section: Membrane Capacitive Deionizationmentioning

confidence: 99%

Frontiers of Membrane Desalination Processes for Brackish Water Treatment: A Review

et al. 2021

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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%

“…MCDI is expected to be less prone to fouling and scaling than other membrane-based desalination technologies [18]. The membranes in MCDI protect the carbon electrodes [19] and due to frequent electrode reversal, build-up of fouling is prevented in a similar way to electrodialysis reversal [15]. MCDI is therefore a potentially highly interesting technology for cooling tower feed pretreatment.…”

Section: Introductionmentioning

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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“…The fouling phenomenon (electrode longevity) is another critical issue that needs to be addressed. Fundamental organic and inorganic fouling experiments have been reported for CDI and ED [ 112 , 113 , 114 , 115 , 116 ], but fouling phenomena are not yet fully understood, as electrochemical processes are in the early stages of research compared to membrane processes. Moreover, a limited number of operations with relatively short cycles (mostly <100) have been reported for electrochemical processes [ 80 , 85 , 86 , 87 ].…”

Section: Perspectives For Future Desalination and The Role Of Nanomentioning

confidence: 99%

Membrane and Electrochemical Processes for Water Desalination: A Short Perspective and the Role of Nanotechnology

2020

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In the past few decades, membrane-based processes have become mainstream in water desalination because of their relatively high water flux, salt rejection, and reasonable operating cost over thermal-based desalination processes. The energy consumption of the membrane process has been continuously lowered (from >10 kWh m−3 to ~3 kWh m−3) over the past decades but remains higher than the theoretical minimum value (~0.8 kWh m−3) for seawater desalination. Thus, the high energy consumption of membrane processes has led to the development of alternative processes, such as the electrochemical, that use relatively less energy. Decades of research have revealed that the low energy consumption of the electrochemical process is closely coupled with a relatively low extent of desalination. Recent studies indicate that electrochemical process must overcome efficiency rather than energy consumption hurdles. This short perspective aims to provide platforms to compare the energy efficiency of the representative membrane and electrochemical processes based on the working principle of each process. Future water desalination methods and the potential role of nanotechnology as an efficient tool to overcome current limitations are also discussed.

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An investigation of the impact of fouling agents in capacitive and membrane capacitive deionisation

Cited by 45 publications

References 38 publications

Frontiers of Membrane Desalination Processes for Brackish Water Treatment: A Review

Frontiers of Membrane Desalination Processes for Brackish Water Treatment: A Review

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

Membrane and Electrochemical Processes for Water Desalination: A Short Perspective and the Role of Nanotechnology

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