Systematic study of an energy efficient MEA-based electrochemical CO2 capture process: From mechanism to practical application

Electrochemically-mediated amine regeneration (EMAR) is a promising technology for CO2 capture, especially in industries where thermal energy is not available. However, the EMAR technology is still at an early stage for commercial application because of its energy-intensive, operating at impractically low current densities, kinetically slow or amine degradation. To solve these problems, we report an energy efficient MEA-based electrochemical CO2 capture process. The redox of copper is the fundamental step in the EMAR process, which determines the energy consumption, energy efficiency and cycling performance of the whole system. A systematic study of the redox reactions of copper ions and the effect of other mediums have been comprehensively studied in this work. Besides, amine oxidative degradation in EMAR has been firstly discussed from the perspective of the solution electrochemical mechanism. Moreover, the copper cycling performance and energy consumption of the proposed system have been carefully studied, results show that a suitable current density and appropriate disturbance are beneficial to improve the circulation performance of the system. The regeneration energy consumption is 60.76 kJ/mol CO2, with a current density of 0.02 A/cm2 and stirring speed of 200 rpm, which is extremely competitive to be used in CO2 capture compared with traditional CO2 chemical absorption methods.