A direct electrochemical substitution electrodialytic system for CO2 conversion into high value-added soda

The growth of CO 2 emissions is a critical challenge to the global ecological system. Meanwhile, the rising use of evaporation units in industrial wastewater treatment plants has generated a large number of salts with low values for further valorization. In this study, a direct electrochemical substitution electrodialytic system is proposed for the conversion of CO 2 and Na 2 SO 4 into high value-added NaHCO 3 and H 2 SO 4 . The CO 2 is absorbed with polyethyleneimine and further metathesized with inorganic salts in an electrodialytic reactor. This unique system achieves soda preparation by avoiding the use of ammonia as a feedstock and demonstrates the ability to capture and convert CO 2 at a specific energy consumption of 1.2 kWh/kg NaHCO 3 and a current efficiency of 83%. This proof-of-concept study provides a highly effective technological pathway for the conversion of notorious wastes into valuable resources, creating possibilities for concurrent carbon reduction and wasted salt utilization.