Bipolar membrane electrodialysis integrated with in-situ CO2 absorption for simulated seawater concentrate utilization, carbon storage and production of sodium carbonate

Abstract

In the context of carbon capture, utilization, and storage, the high-value utilization of carbon storage presents a significant challenge. To address this challenge, this study employed the bipolar membrane electrodialysis integrated with carbon utilization technology to prepare Na₂CO₃ products using simulated seawater concentrate, achieving simultaneous saline wastewater utilization, carbon storage and high-value production of Na₂CO₃. The effects of various factors, including concentration of simulated seawater concentrate, current density, CO₂ aeration rate, and circulating flow rate of alkali chamber, on the quality of Na₂CO₃ product, carbon sequestration rate, and energy consumption were investigated. Under the optimal condition, the CO₃^2- concentration in the alkaline chamber reached a maximum of 0.817 mol/L with 98 mol% purity. The resulting carbon fixation rate was 70.50%, with energy consumption for carbon sequestration and product production of 5.7 kWhr/m³ CO₂ and 1237.8 kWhr/ton Na₂CO₃, respectively. This coupling design provides a triple-win outcome promoting waste reduction and efficient utilization of resources.

Keywords: Bipolar membrane electrodialysis (BMED); Carbon capture; Seawater concentrate; Sodium carbonate; Utilization and storage (CCUS).