Techno-Economic\nAssessment of Brackish Water Electrochemical\nDesalination with Faradaic Electrodes

Capacitive deionization (CDI) has\nbeen widely studied for low-salinity\ndesalination because of low-voltage operation, tunable salinity removal,\nand likely tolerance against fouling and scaling. Replacing carbonaceous\nelectrodes with faradaic electrodes in CDI systems can increase both\nthe energy efficiency and salt adsorption capacity. However, the techno-economic\ncompetitiveness of faradaic-based deionization systems versus carbon-electrode-based\nCDI and reverse osmosis (RO) remains unclear. In this study, we develop\na parametric model to estimate the levelized cost of water (LCOW)\nproduced by CDI, membrane CDI, and three architectures of faradaic-based\ndeionization systems (hybrid deionization, dual-ion deionization,\nand battery deionization). We also investigate how different faradaic\nmaterials, operation conditions, and cell designs would impact the\nLCOW. Battery deionization outperforms hybrid deionization and dual-ion\ndeionization in terms of LCOW. Additionally, in the scenario of a\nfixed 0.5-year lifespan, a lower LCOW of battery deionization is achieved\nat a higher ASAR with a lower thermodynamic energy efficiency; as\nsuch, operating at a higher current density can be a helpful strategy\nfor reducing the cost of water production. Finally, sensitivity analysis\nindicates that electrode longevity and ion exchange membrane price\nare crucial parameters toward cost reduction of BDI to be cost-competitive\nwith RO.