Absorption and solubility measurement of CO2 in water-based ZnO and SiO2 nanofluids

The experiments of the absorption of carbon dioxide in the water-based nanofluids of spherical silica (SiO2) and zinc oxide (ZnO) nanoparticles are carried out in an isothermal stirred high pressure cell using quasi-static method through gas pressure measurement. The SiO2 and ZnO nanoparticle compounds were purchased and synthesized, respectively; and characterized through X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM) images. Moreover, the zeta potential is measured to show the stability of these nanoparticles in water. The experiments are performed at 2, 5 and 8 degrees C and a range 1 bar up to gas hydrate equilibrium pressure; and in 15, 25 and 40 degrees C at 1-36 bar. The CO2 solubility measurement in pure water and the 0.1 wt% of the two nanofluids show that the amount of the absorbed CO2 enhances in presence of nanoparticles so that the ZnO nanofluids are more effective than SiO2 nanofluids at the all experimental conditions. In addition, the solubility of CO2 is measured in the 0.05, 0.1, 0.5 and 1 wt% of ZnO nanofluid at 5 degrees C and pressure range of 1-22 bar so that the amount of absorption was enhanced by increasing the ZnO mass loading at the all measurements. The mechanism of CO2 absorption in the nanofluids are fully discussed and compared with those gas solubility results in pure water. (C) 2015 Elsevier B.V. All rights reserved.