Investigation on the performance of EDA-based blended solvents for electrochemically mediated CO2 capture

Abstract

EDA-Cu based electrochemically mediated CO2 capture method was developed as a promising technology to substitute the conventional amine-based CO2 capture, especially in industries without available steam source. However, the highly corrosive and poor Cu cycling performance seriously obstruct its large-scale application. In this work, traditional primary amine, secondary amine and tertiary amine (MEA, DEA and TEA) are chosen to blend with EDA to alleviate the problems of EDA. Electrochemical measurements, corrosiveness comparison, CO2 absorption and desorption performance were conducted to investigate the advance performance of proposed blended solvents comprehensively. The corrosion potential in all the mixtures is significantly higher than that in sole EDA solution, which illustrates that the corrosiveness of proposed mixed solvents to Cu electrode is weaker. Besides, the Cu cycling performance is greatly improved and the energy consumption is significantly reduced by using blended solvents. Overall, 50/50 EDA/MEA mixed solution with high CO2 capacity and fast absorption rate is suggested to be a substitute for traditional EDA solvent. The CO2 desorption energy consumption of 50/50 EDA/MEA mixed solution decreases 14% than that of EDA solution at a current density of 0.01 A/cm2. Meanwhile, the copper cycling performance is also improved in 50/50 EDA/MEA mixed solution as the cathode Faraday efficiency (CFE) increased from 43% (EDA) to 53% (50/50 EDA/MEA). Results show that the proposed mixed amine solvents lead to the successful circumvention of highly corrosive and poor Cu cycling performance in the electrochemically mediated CO2 capture system, which will contribute to the exploration of efficient blended solvents for EMAR CO2 capture process and promote its industrial application.