Experimental solubility of CO2 and CH4 in imidazolium based ionic liquid; [C6mim][BF4] at high pressures

The solubility*of carbon dioxide (CO₂) in fresh and recycled ionic liquid (IL); 1-hexyl-3-methyl imidazolium tetrafluoroborate [C₆mim][BF₄] was experimentally measured at three different temperatures i.e., 303.15 K, 318.15 K, 333.15 K and pressures up to 60 bar. The solubility of CO₂ and Methane (CH₄) in fresh IL; [C₆mim][BF₄] was also measured using binary mixtures of CO₂ and CH₄ i.e., 60/40 (B₆₄) and 40/60 (B₄₆) volume percent at temperatures (303.15 K, 318.15 K, 333.15 K) and pressures up to 60 bar. The solubility measurements for both gases were performed in a specifically designed high pressure miniature gas solubility cell. The solubility of CO₂ and CH₄ in the studied IL increased almost linearly with an increase in pressure and decreased with an increase in temperature and no significant difference was observed for the amount of CO₂ absorbed in fresh and recycled IL at the studied range of operating conditions. It was observed that the presence of CH₄ significantly reduced the solubility of CO₂ in the studied IL.