Carbon dot-blended mixed amine for efficient CO2 capture under highly oxidative flue gas conditions

In the pursuit of developing efficient aqueous solutions for reversible CO₂ capture in post-combustion carbon capture processes, the blending of amine solvents with advanced properties has emerged as a strategic approach. Regardless of several advantages of this method, challenges persist, particularly under high oxidative feed conditions, including amine component degradation, foaming, and low rich and lean loading. In this study, we address these inherent issues by investigating the potential of carbon dots (CDs) as additives to augment the performance of mixed amines consisting of Methyl diethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP) and Piperazine. Pilot scale operations at a 30 L solvent scale revealed that the CDs-additized mixed amine formulation exhibited robust performance over a continuous 200 h operation. The CDs-additized solvent exhibited a 23% higher rich loading than the non-additized counterpart, primarily due to enhanced mass transfer rather than the change in equilibrium loading. Additionally, the CDs-additized mixed amine solvent exhibited reduced foaming tendencies and approximately 16% lower regeneration energy consumption, even after prolonged continuous operation under oxidative flue gas condition. To evaluate the component degradation of the mixed amine solvent, a rapid and accurate Ionic chromatography (IC)-based method was developed. The present findings suggest that the CDs-additized mixed amine system holds promise as an efficient solvent for low-cost CO₂ capture processes, ultimately contributing to the reduction of operational expenses in the CO₂ capture process.