Enhancing CO2 uptake by aqueous K2CO3 solutions using H2O2-derived reactive oxygen species: Novel rate promotion for CCU processes

Abstract

This study introduces a novel approach to promote CO₂ absorption by aqueous K₂CO₃ solutions through the in-situ generation of reactive oxygen species (ROS) via the alkali activation of H₂O₂. The superoxide radical anion (O₂^•-) is recognized as a major contributor in this process, with its presence confirmed by UV-Vis (Ultraviolet–visible) spectroscopy through the characteristic diformazan peak formed from the reaction between nitro blue tetrazolium (NBT) and superoxide. CO₂ absorption experiments and ¹³C NMR (Carbon-13 nuclear magnetic resonance) characterization demonstrate the enhanced efficiency of the promoted solution in both CO₂ absorption and the conversion of K₂CO₃ to KHCO₃. Comparative analysis with traditional promoters reveals the superior kinetic performance of the H₂O₂-promoted system at room temperature. Notably, our system yields pure KHCO₃ without by-products, making it highly suitable for carbon capture and utilization (CCU) by enabling versatile subsequent transformation processes. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.