Study of Absorption Enhancement of CO2 by SiO2, Al2O3, CNT, and Fe3O4 Nanoparticles in Water and Amine Solutions

In this work, the absorption process of carbon dioxide is performed in a custom designed high pressure experimental setup in which the gas and nanofluid are in direct contact at static state in a closed vessel. The initial condition of the tests are set at 20, 30, and 40 bar and 308 K. Nanoparticles of SiO 2, Al 2 O 3, Fe 3 O 4, and carbon nanotubes (CNTs) are dispersed in pure water to form nanofluids at concentrations of 0.02, 0.05, and 0.1 wt %. Also, CNT nanoparticle has been dispersed in methyldiethanolamine and diethanolamine aqueous solutions at the concentration of 0.02 wt %. The absorption performances of different nanofluids are compared with the base solutions and with other nanofluids at different conditions. The results show that SiO 2 and Al 2 O 3 are more effective at higher nanoparticle concentrations (0.1 wt %), and they can enhance the absorption capacity up to 21% and 18%, respectively. Fe 3 O 4 and CNT are more effective at lower nanoparticle concentration (0.02 wt %), and they can increase it up to 24% and 34%, respectively. CNT nanoparticle is more effective for methyldiethanolamine solution compared to diethanolamine solution with an increase in the absorption capacity up to 23%. It seems that gas adsorption on the nanoparticles surface leads to higher absorption capacity of nanofluids at equilibrium condition.