Significance　Ionic　liquids　(ILs)　are　employed　for　air-drying　for　the　first　time.　The　experimental　gas-liquid　equilibrium　(EQ)　of　N-2/O-2+[EMIM][BF4]　and　N-2/O-2+[EMIM][BF4]+H2O　systems　under　a　broad　temperature　range　are　measured.　The　new　modified　UNIFAC-Lei　model　is　successfully　extended　to　predict　the　N-2/O-2-IL-H2O　system　based　on　extensive　phase　EQ　data.　The　air-drying　experiment　using　[EMIM][BF4]　as　an　absorbent　is　conducted,　confirming　that　this　new　technology　is　effective　and　efficient.　(c)　2018　American　Institute　of　Chemical　Engineers　AIChE　J,　65:　479-482,　2019