CO2 mineralization as a promising CO2 mitigation strategy can employ industrial alkaline solid wastes to achieve net emission reduction of atmospheric CO2.The red mud is a strong alkalinity waste residue pro-duced from the aluminum industry by the Bayer process which has the potential for the industrial CO2 large scale treatment.However,limited by complex components of red mud and harsh operating condi-tions,it is challenging to directly mineralize CO2 using red mud to recover carbon and sodium resources and to produce mineralized products simultaneously with high economic value efficiently.Herein,we propose a novel electrochemical CO2 mineralization strategy for red mud treatment driven by hydrogen-cycled membrane electrolysis,realizing mineralization of CO2 efficiently and recovery of car-bon and sodium resources with economic value.The system utilizes H2 as the redox-active proton carrier to drive the cathode and anode to generate OH-and H+at low voltage,respectively.The H+plays as a neutralizer for the alkalinity of red mud and the OH-is used to mineralize CO2 into generate high-purity NaHCO3 product.We verify that the system can effectively recover carbon and sodium resources in red mud treatment process,which shows that the average electrolysis efficiency is 95.3％with high-purity(99.4％)NaHCO3 product obtained.The low electrolysis voltage of 0.453 V is achieved at 10 mA·cm-2 in this system indicates a potential low energy consumption industrial process.Further,we successfully demonstrate that this process has the ability of direct efficient mineralization of flue gas CO2(15％volume)without extra capturing,being a novel potential strategy for carbon neutralization.

Heping Xie;Yunpeng Wang;Tao Liu;Yifan Wu;Wenchuan Jiang;Cheng Lan;Zhiyu Zhao;Liangyu Zhu;Dongsheng Yang

School of Chemical Engineering,Sichuan University,Chengdu 610065,China;Institute of Deep Earth Science and Green Energy,Shenzhen University,Shenzhen 518060,China;Institute of New Energy and Low-Carbon Technology,Sichuan University,Chengdu 610065,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China

中国化学工程学报（英文版）

[1]Heping Xie;Yunpeng Wang;Tao Liu;Yifan Wu;Wenchuan Jiang;Cheng Lan;Zhiyu Zhao;Liangyu Zhu;Dongsheng Yang-.Electrochemical CO2 mineralization for red mud treatment driven by hydrogen-cycled membrane electrolysis)[J].中国化学工程学报（英文版）,2022(03):14-23

H+at,H+plays,neutralizer

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