Development of an Electrochemical Acidification Cell for the Recovery of CO2 and H2 from Seawater II. Evaluation of the Cell by Natural Seawater

A novel electrochemical acidification process has been developed in a successful feasibility attempt to extract large quantities of CO2 in the form of bicarbonate and carbonate from seawater for potential use as a source of carbon for hydrocarbon production at sea. This indirect approach acidifies seawater by the electrolytic production of acid. Lowering seawater pH was found to be proportional to the applied current to the cell. Spontaneous degassing and recovery of CO2 below pH 4.5 was reduced from 92% in synthetic seawater to 30% in natural seawater. The effects of increased operational time, flow rate, current, and natural seawater’s complex equilibrium buffer on process performance and CO2 recovery have been shown to be essential for further improvements in future cell design, efficiency, and scale-up.