Potential Application of Membrane Capacitive Deionization for Heavy Metal Removal from Water: A Mini-Review

Abstract

Heavy metal pollution of the aquatic environment has become a global concern in recent decades, and conventional methods for heavy metal removal, like coagulation, precipitation, and membrane filtration, have their limitations. In this mini-review, we discuss four aspects of heavy metal removal by membrane capacitive deionization (MCDI): i) the role of electrode materials; ii) role of ion-exchange membrane; iii) operating conditions; and iv) water chemistry. Based on this discussion, we determine MCDI to have good potential for heavy metal removal in water. Future MCDI studies should focus on synthesizing ionselective electrode to promote the removal of specific ionic species; developing multifunctional electrodes for the simultaneous removal of different heavy metals; performing pilot-scale studies instead of bench-scale ones; applying MCDI to raw water or real-life water samples and controlling MCDI with different current modes.

Electrochemical Methods for Water Purification, Ion Separations, and Energy Conversion

“…A number of emerging applications use CDI for water purification, including desalination of brackish water and selective electrosorption of target ions. ,,− While electrosorption is generally limited to removal of charged species, porous carbons have the well-known ability to adsorb organic compounds, which can enable simultaneous removal of salt and uncharged organic contaminants by CDI . Many novel designs and cell architectures have been invented and characterized, such as membrane CDI (MCDI, see Figure ) ,− and flow electrode CDI (FCDI, Figure b). − MCDI can improve cell cycle life and energy efficiency, and FCDI enables continuous desalination using a single CDI cell. Moreover, the structure of CDI cells can be categorized as either flow-between (FB) or flow-through electrode (FTE), depending on the direction of the feed.…”

Design, synthesis, and performance of adsorbents for heavy metal removal from wastewater: a review

“…1), adsorption has attracted the most attention due to its simple procedure, easy operation, and low cost. Numerous excellent review articles have evaluated the development of specific novel adsorbents (such as chitosan, 7 nanomaterials, 8 and one-dimensional carbon nanotubes 9 ) and integration of adsorption with other technologies (like biosorption 10 and membrane capacitive deionization 11 ). However, a comprehensive assessment on the recent progress of the adsorption removal technique is necessary.…”

Nano-hydroxyapatite-assisted enzyme-induced carbonate precipitation enhances Pb-contaminated aqueous solution and loess remediation

“…To tackle the said issue, many remediation technologies applied for Pb immobilization have been developed ( Bai et al, 2022 ; Xie et al, 2022 ; Xue et al, 2022 ; Xue et al, 2023 ). However, they are often criticized due to poor performance and are accompanied by a high risk of secondary contamination ( Yang et al, 2020 ; Meng et al, 2022 ; Hu et al, 2023a ; Hu et al, 2023b ; Wang et al, 2023 ; Bai et al, 2024 ; Xue et al, 2024b ).…”