(Invited) Coupling Process Driven Technoeconomic Modeling and Material Development to Chart a Commercialization Pathway for Electrochemical Nutrient Separation Technologies

TL;DR: Technoeconomic modeling and material development to optimize the cost-effectiveness of capacitive deionization for nutrient removal. The impact of ion selectivity on CDI system cost is analyzed, showing that millimolar concentration contaminants can be removed at costs in the range of $0.01–0.30 m-3.

Abstract: Removal and recovery of nutrient oxyanions such as nitrate and phosphate remains challenging due to the high capital and environmental costs associated with common technologies such as reverse osmosis or ion exchange. Capacitive deionization (CDI) is a promising technology for selective ion removal due to high reported ion selectivity at dilute target ion concentrations and low operating costs. However, the impacts of material ion selectivity and influent water characteristics on CDI life cycle cost have not been considered. In this talk we present the impact of ion selectivity on CDI system cost with a parameterized process model and technoeconomic analysis framework. Simulations indicate millimolar concentration contaminants such as nitrate can be removed at costs in the range of $0.01–0.30 m-3 at reported selectivity coefficient ranges (S = 6–10). To contextualize simulated results for CDI treatment of NO3 -, CDI unit operations were sized and costed for three cases studies based on existing treatment facilities in Israel, Spain, and the United States, showing that achieving a nitrate selectivity of 10 could reduce life cycle treatment costs below $0.2 m-3 if a system lifetime of 24,000 cycles could be achieved. This talk will also discuss the inclusion of faradaic polymer coatings as a strategy to increase both target ion selectivity and electrode longevity.