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

Abstract

The growth of CO2 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 CO2 and Na2SO4 into high value-added NaHCO3 and H2SO4. The CO2 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 CO2 at a specific energy consumption of 1.2 kWh/kg NaHCO3 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.