Selective adsorption of carbon dioxide over nitrogen on calcined synthetic hectorites with tailor-made porosity

Hectorites were synthesized using 1-butyl-3-methylimidazolium bromide, 1,3-didecyl-2-methylimidazolium chloride and 1-decyl-3-methylimidazolium chloride as synthesis directing agents at condensation temperature for 48 h. Calcinations of synthetic hectorites resulted mesoporous materials with pore diameters ranging from 3.4 to 5.5 nm. The pore diameters depended on the directing agent. Synthetic and calcined hectorites were characterized by powder X-ray diffraction. Adsorption properties of CO2 and N2 on calcined hectorites were investigated by volumetric measurements. The adsorption capacity for CO2 and N2 decreased with increasing pore diameter. The calcined hectorites showed very good selectivity for CO2 over N2 at lower as well as higher partial pressure at 303 K.