Feasibility of CO2 Extraction from Seawater and Simultaneous Hydrogen Gas Generation Using a Novel and Robust Electrolytic Cation Exchange Module Based on Continuous Electrodeionization Technology

A novel, robust, and innovative electrolytic cation exchange process has been used to efficiently extract large quantities of CO2 in the form of bicarbonate and carbonate from natural seawater, and to simultaneously produce H2 gas in quantities and ratios intended for possible future production of hydrocarbons. This indirect approach acidifies seawater by using the protons electrolytically produced by electrolysis at the anode. Electrons concurrently produced with these protons are subsequently consumed at the cathode forming hydrogen gas. The ability to degas and recover 92% [CO2]T from natural seawater was demonstrated. The potential detrimental effects of mineral deposits on the module's electrode surfaces were successfully mitigated by cyclically changing the module electrode's polarity. This feasibility study marks the first time that CO2 has been successfully extracted on a continuous basis from natural seawater. In addition, there is no energy or economic penalty to extract CO2 from the seawater matrix, above the energy needed to produce hydrogen.