Collaborative disposal of problematic calcium ions in seawater and carbon and sulfur pollutants in flue gas by bipolar membrane electrodialysis

• Published in: Desalination 2020-11, Vol.494, p.114654, Article 114654
• Main Authors: Zhao, Yingying, Wang, Lurong, Ji, Zhiyong, Liu, Jie, Guo, Xiaofu, Li, Fei, Wang, Shizhao, Yuan, Junsheng
• Format: Article
• Language: English
• Subjects: Bipolar membrane electrodialysis; Carbon capture & storage; Flue gas desulfurization; Seawater decalcification
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2020.114654

The scale pollution caused by calcium ions (Ca2+) in seawater limits the development of seawater desalination. Emissions of CO2 and SO2 in flue gas can cause environmental problems. Under alkaline conditions, Ca2+ in seawater and CO2 in flue gas are precipitated while SO2 in flue gas is ionized. Based on the removal of calcium and carbon sequestration by bipolar membrane method, this study explored the feasibility of flue gas carbon fixation and desulfurization by seawater in the electrodialysis device. The effects of current density, aeration, CO2 content and the crystal form of seeds on pollutant treatment were investigated. The results indicated that the lower energy consumption can be obtained when the current density was 12.5 A/m2, the flue gas flow rate was 40 L/h and the CO2 content was 10% in flue gas, which established an operating conditions to obtain the decalcification rate greater than 90%, the carbon fixation rate up to 30% and the desulfurization rate close to 100%. Aragonite polymorph of calcium carbonate can be obtained regardless of polymorph of seeds in flue gas. Therefore, bipolar membrane electrodialysis integrated gas absorption and ionic reaction in order to overcome the pollution caused by the addition of traditional chemical reagents. •An alkaline environment was continuously provided by BMED system to absorb acid gases.•Directly use calcium ions in raw seawater to fix carbon dioxide in flue gas without the ion exchange membrane contaminated.•Carbon and sulfur from the flue gas were fixed and removed selectively in the form of solid and liquid phases.•The feasibility of the application of bipolar membrane electrodialysis was further verified in gas-liquid-solid systems.