The influence of TBAC additive on performance of electrochemically mediated amine regeneration

Electrochemical-mediated amine regeneration (EMAR) is a promising carbon capture technology. It uses an electrochemical process to regenerate amine solutions, replacing conventional thermal methods. This substitution significantly reduces the energy consumption and cost of amine-based CO 2 capture. However, challenges such as slow reaction kinetics and relatively high energy requirements have hindered its commercial adoption. In this work, these limitations are overcome for the first time by introducing additives into the EMAR electrolyte. The amine regeneration performance of mixed solutions incorporating five different additives including β-Cyclodextrin (β-CD), Trisodium phosphate (TSP), Glycine (Gly), 3-Mercapto-1-propanesulfonic acid (MPS), Tetrabutylammonium chloride (TBAC) was systematically evaluated, and the mechanistic role of these additives in the electrochemical regeneration process was thoroughly investigated. Results indicate that TBAC serves as an effective additive that enhances the overall performance of monoethanolamine (MEA) solution within the EMAR system. In terms of CO 2 absorption, the MEA solution with TBAC outperformed those with other additives, achieving higher CO 2 loading capacity and faster absorption kinetics. Furthermore, electrochemical analyses revealed that the reduction of Cu 2+ is facilitated in the TBAC-modified MEA solution compared to other additive systems, while the anodic oxidation of metallic copper to Cu 2+ is also enhanced. Notably, the TBAC-modified MEA solution exhibited significantly improved CO 2 desorption performance. The measured desorption energy consumption for the TBAC system was lower, coupled with higher Faradaic efficiency. Specifically, at a current density of 100 A/m 2 , the desorption energy consumption was determined to be 19.48 kJ/mol CO 2 , demonstrating strong potential for industrial implementation of the EMAR process.