The　aim　of　the　present　study　is　to　investigate　the　effectiveness　of　bi-metallic　LSX　zeolites　containing　extra-framework　cations　in　removing　and　purifying　O2　from　the　air.　Li-LSX　zeolite　was　synthesized　first　from　Na-LSX　and　then　replaced　the　unused　Li-cations　present　in　Li-LSX　with　small　fractions　(20　%)　and　enough　(90　%)　of　other　cations　(Na+,　Li+,　Ca2+,　Mg2+,　and　Ag+)　to　reduce　Li　content.　This　process　led　to　the　preparation　of　bi-metallic　Mx,　Nay-LSX,　and　Mx,　Liz-LSX　zeolites　via　ion　exchange　and　mild　dehydration　to　prevent　Li　cation　migration.　The　equilibrium　adsorption　isotherms　of　pure　N2/O2　gases　at　273　and　298　K　and　the　selectivities　of　adsorption　for　Mx,　Nay-LSX,　and　Mx,　Liz-LSX　zeolites　are　compared　with　those　for　pure-cations　Li-,　Ca-,　Mg-,　and　Ag-LSX.　The　results　showed　that　bi-metallic　zeolites　produced　significantly　higher　O2　yields　with　the　same　product　purity　and　recovery　as　the　neat　cation　precursors.　The　results　revealed　that　the　exponential　increase　in　N2　adsorption　in　Mx,　Liz-LSX　zeolites　compared　to　Mx,　Nay-LSX　after　the　addition　of　the　second　metal　cation　(M+)　to　Li-LSX　was　due　to　the　significant　influence　of　the　nature,　location,　ionic　radius,　charge　density,　level　of　the　extra　framework　cations,　and　following　electrostatic　forces　of　attraction　between　the　extra-framework　cations　and　the　adsorbed　molecules.　Prediction　of　binary　components　(O2-N2)　was　made　via　IAST　(ideal　adsorbed　solution　theory)　by　using　pure　adsorption　component　isotherm　data　and　Dual-site　Langmuir　equation.　The　research　suggests　that　bi-metallic　LSX　zeolites　have　excellent　potential　as　N2　selective　adsorbents　for　separating　and　purifying　O2　from　the　air.　©　2024　Elsevier　Ltd