Sorption equilibria of CO2 on silica-gels in the presence of water

Abstract

The sorption equilibria of carbon dioxide on three types of silica gel (SG) with different pore size distributions in the presence of water were studied experimentally using a volumetric method at 275 K with pressures from 0 to 3.7 MPa. Both the pore size distribution of the silica gel and the quantity of pre-sorbed water impact the formation of the CO2 hydrates. For wet silicon gel A(SG-A) with water loading ratio of 0.75, the highest CO2 sorption was about 2.5 mmol of CO2 per gram of dry sorbent at 275 K. Similarly, the highest sorption was about 2.7 mmol for wet SG-B with Rw=0.81. However, CO2 hydrate did not form on the wet surface of SG-C due to its large pore sizes.