Electrodeposition of Carbon-Trapping Minerals in Seawater for Variable Electrochemical Potentials and Carbon Dioxide Injections

Abstract

Seawater offers immense potential for addressing global energy and climate challenges. Electrochemical seawater splitting is a sustainable approach for hydrogen production and carbon dioxide (CO₂) sequestration, producing hydrogen gas at the cathode and oxygen or chlorine gas at the anode. Simultaneously, minerals such as calcium carbonate and magnesium hydroxide precipitate at the cathode, especially when coupled with CO₂ injections for the sake of CO₂ sequestration. These precipitates are often dismissed as energy-intensive byproducts. However, they have untapped potential as resources for construction, manufacturing, and environmental remediation. Here, a comprehensive experimental investigation is presented into the electrochemical precipitation of minerals in seawater under varying operational conditions. By systematically varying applied voltage, current density, and CO₂ flow rate, the conditions that optimize mineral yield and selectivity while minimizing energy consumption are revealed. The findings advance the understanding of electrochemical synthesis and material processing in aqueous solutions, with a particular focus on the mineralization of calcareous compounds and their transformation into large-scale aggregates. These findings also support an additional and highly scalable application of seawater electrolysis, encompassing not only oceanic renewable hydrogen production and CO₂ sequestration but also the sustainable production of carbon-trapping minerals and aggregates.