Abstract
Enhancing CO₂ absorption efficiency in amine-based solvents remains a major challenge for post-combustion capture systems. In this study, CO₂ absorption was investigated using aqueous monoethanolamine (MEA) solutions containing metal oxide nanoparticles (Al₂O₃ and MgO) in a T-shaped microchannel with a diameter of 800 μm and a length of 25 cm. Experiments were conducted at atmospheric pressure with 10.0 vol% CO₂ in the feed gas. The key operating parameters included solvent concentration (5.0 and 10.0 vol% MEA) and nanoparticle loading (0.01, 0.05, and 0.1 wt%). Under optimal conditions (25.0 °C, solvent flow rate 200 mL/h, gas flow rate 100 mL/min), the CO₂ absorption efficiencies of 5.0 vol% and 10.0 vol% MEA were 75.6% and 84.8%, respectively. When nanofluids were used with 5.0 vol.% MEA at a nanoparticle concentration of 0.05 wt.% (Al₂O₃ or MgO), absorption efficiencies increased to 95.3% and 98.3%, corresponding to improvements of 19.7% and 22.7% over the base solvent. MgO nanofluid also exhibited superior CO₂ desorption performance compared with Al₂O₃. At desorption conditions (95.0 °C, nanofluid flow rate 100 mL/h, 10.0 vol% MEA), removal efficiencies of 97.1% and 98.9% were achieved. This study provides the experimental demonstration of CO₂ absorption and desorption intensification using MEA based nanofluids in a T-shaped microchannel, revealing the unique microscale mass transfer enhancement induced by Al₂O₃ and MgO nanoparticles.