Oceanic carbon capture through electrochemically induced in situ carbonate mineralization using bipolar membrane

Bipolar membrane electrodialysis (BPMED) can provide a sustainable route to capture the oceanic-dissolved inorganic carbon (DIC) using an electrochemical pH-swing concept. Previous works demonstrated how gaseous CO2 (through acidification) be obtained from ocean water, and carbonate minerals provided via ex situ alkalinization. In this work, we present, for first time, in mineralization alkalinization both real synthetic seawater. An pH-swing, inside of BPMED cell, allows reducing energy consumption oceanic-DIC capture. We demonstrate that, by accurately controlling applied current density cell residence required process indeed lowered through facilitating optimized pH (i.e., base-pH 9.6–10). Within alkaline pH-window, between 60% (for seawater) up 85% DIC feed, together with minor Mg(OH)2 precipitates. The CaCO3(s) production increases linearly density, theoretical maximum extraction 97 %. is dominated ohmic losses BPM-overpotential. Through tuning flow rate, optimised applying mild ca. 3.2 – 9.75 seawater). As result, aragonite was extracted 318 ± 29 kJ mol?1 0.88 kWh kg?1 CaCO3(s)) seawater containing ten bipolar cation exchange pairs, which less than half previously lowest (synthetic)