Membrane Capacitive Deionization Using Ion-exchange Polymer Coated Electrodes for Resource Recovery from Wastewater

Publication Type:
Thesis
Issue Date:
2020
Full metadata record
Resource recovery from wastewater has become attractive where technological innovation is being used to provide additional social, environmental, and economic benefits. This study therefore aimed to explore the application potential of MCDI for recovering valuable resources from wastewater, especially converging the ion selectivity and performance efficiency during electrosorption and electrode regeneration. Carbon electrodes coated with a thin ion-exchange polymer layer were mainly used for both inducing lower membrane electrical resistance and inhibiting the electrosorption of the counter-ions during regeneration. The enrichment of target ions from low concentration was challenging due to the reverse-ionic-strength gradient induced by the highly enriched brine solutions. Selective recovery of nitrate could be enhanced by increasing relative ion mobility and water flow rate, whereas selective collection of phosphate was difficult due to its low permselectivity and low amount present in wastewater. Better adsorption of target species could be realized by customizing the electrodes with coating an ion selective polymer layer. The application of MCDI can be expanded on recovery of precious metals such as palladium through establishing proper strategies to inhibit physisorption of the metallic species. The outcomes from this work may provide future insights into designing practical MCDI process with optimum selectivity of target ions.
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