The addition of dispersed-phase nanoparticles in the liquid phase can enhance the gas-liquid transfer process as the suspended nanoparticles affect the transfer process inside the fluid through microdisturbance or micro-convection effects. In this article

a high-speed digital camera was used to visualize the bubble behavior of CO

2

in pure water and nanofluids to examine the effects of CO

2

gas flow rate

nanoparticle solid content and type on the bubble behavior in the fluids. The CO

2

absorption performance in three water-based nanofluids were compared in a bubbler. And the mass transfer characteristics during CO

2

bubble absorption and the reasons for the enhanced gas-liquid mass transfer effect of nanoparticles were analyzed. The results showed that the presence of nanoparticles affected the formation process of bubbles in the fluid

shortened the bubble detachment time

reduced the detachment diameter

effectively increased the gas-liquid contact area

and improved the bubbles detachment frequency. The system with MCM-41 corresponded to a higher overall mass transfer coefficient. Uncalined MCM-41 contained surfactant that enhanced foaming behavior in water. This prevented the transfer of CO

2

to some extent

and the CO

2

absorption by uncalined MCM-41/H

2

O was 5.34% higher than that by pure water. Compared with SiO

2

nanoparticles with the same particle size and the same composition

MCM-41

had a higher adsorption capacity and better hydrophilicity due to its larger specific surface area and rich porous structure

which was more favorable to accelerate the collision between nanoparticles and CO

2

bubbles to cause micro-convection. Under the condition of≥0.1% (mass) solid content

the enhancement of CO

2

absorption process by MCM-41 nanoparticles was more significant and improved by 16.9% compared with pure water.