A sustainable bipolar membrane electrodialysis process for effective conversion of CO2 and NaCl brine into NaHCO3.

Climate change demands innovative carbon capture and utilization (CCU) strategies, yet converting captured CO2 into high-value products while managing industrial waste remains elusive. Here, we demonstrate a single-step, energy-efficient bipolar membrane electrodialysis (BMED) system integrated with CCU, enabling the simultaneous conversion of NaCl brine and CO2 into high-purity sodium bicarbonate (NaHCO3) with unprecedented efficiency, but without requiring external alkali sources or energy-intensive thermal regeneration steps. By optimizing key parameters - such as current density and CO2 aeration rate, and gas-liquid flow ratios - we achieved a bicarbonate concentration of 1.186 mol/L in the alkaline chamber, coupled with 57.65% carbon sequestration efficiency and an energy consumption as low as 3.1 kW·h/m³ CO2 (or 716.9 kW·h/t NaHCO3). This approach not only recovers valuable sodium resources from brine but also enhances CO2 absorption through electrochemical mechanisms, potentially reducing global carbon emissions by up to 20% in brine-intensive industries. Our work paves the way for scalable, sustainable CCUS technologies, transforming waste streams into economic assets and advancing the fight against climate change.